C Programming :: Strings
1. Which of the following function sets first n characters of a string to a given character?
A.strinit()
B.strnset()
C.strset()
D.strcset()
Answer: Option B
Explanation:char *strnset(char *s, int ch, size_t n); Sets the first n characters of s to ch
#include <stdio.h>
#include <string.h>
int main(void)
{
char *string = "abcdefghijklmnopqrstuvwxyz";
char letter = 'x';
printf("string before strnset: %s\n", string);
strnset(string, letter, 13);
printf("string after strnset: %s\n", string);
return 0;
}
Output:
string before strnset: abcdefghijklmnopqrstuvwxyz
string after strnset: xxxxxxxxxxxxxnopqrstuvwxyz
2. If the two strings are identical, then strcmp() function returns
A.-1
B.1
C.0
D.Yes
3. How will you print \n on the screen?
A.printf("\n");
B.echo "\\n";
C.printf('\n');
D.printf("\\n");
Answer: Option D
Explanation:The statement printf("\\n"); prints '\n' on the screen.
4. The library function used to find the last occurrence of a character in a string is
A.strnstr()
B.laststr()
C.strrchr()
D.strstr()
5. Which of the following function is used to find the first occurrence of a given string in another string?
A.strchr()
B.strrchr()
C.strstr()
D.strnset()
Answer: Option C
Explanation:The function strstr() Finds the first occurrence of a substring in another string
Declaration: char *strstr(const char *s1, const char *s2);
Return Value:
On success, strstr returns a pointer to the element in s1 where s2 begins (points to s2 in s1).
On error (if s2 does not occur in s1), strstr returns null.
Example:
#include <stdio.h>
#include <string.h>
int main(void)
{
char *str1 = "IndiaBIX", *str2 = "ia", *ptr;
ptr = strstr(str1, str2);
printf("The substring is: %s\n", ptr);
return 0;
}
Output: The substring is: iaBIX
6. Which of the following function is more appropriate for reading in a multi-word string?
A.printf();
B.scanf();
C.gets();
D.puts();
Answer: Option C
Explanation:gets(); collects a string of characters terminated by a new line from the standard input stream stdin
#include <stdio.h>
int main(void)
{
char string[80];
printf("Enter a string:");
gets(string);
printf("The string input was: %s\n", string);
return 0;
}
Output:
Enter a string: IndiaBIX
The string input was: IndiaBIX
7. Which of the following function is correct that finds the length of a string?
A.int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
{ length++; s++; }
return (length);
}
B.int xstrlen(char s)
{
int length=0;
while(*s!='\0')
length++; s++;
return (length);
}
C.int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
length++;
return (length);
}
D.int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
s++;
return (length);
}
Answer: Option A
Explanation:option A is the correct function to find the length of given string.
Example:
#include<stdio.h>
int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
{ length++; s++; }
return (length);
}
int main()
{
char d[] = "IndiaBIX";
printf("Length = %d\n", xstrlen(d));
return 0;
}
Output: Length = 8
8.What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str1[20] = "Hello", str2[20] = " World";
printf("%s\n", strcpy(str2, strcat(str1, str2)));
return 0;
}
A.Hello
B.World
C.Hello World
D.WorldHello
Answer: Option C
Explanation:Step 1: char str1[20] = "Hello", str2[20] = " World"; The variable str1 and str2 is declared as an array of characters and initialized with value "Hello" and " World" respectively.
Step 2: printf("%s\n", strcpy(str2, strcat(str1, str2)));
=> strcat(str1, str2)) it append the string str2 to str1. The result will be stored in str1. Therefore str1 contains "Hello World".
=> strcpy(str2, "Hello World") it copies the "Hello World" to the variable str2.
Hence it prints "Hello World".
9. What will be the output of the program ?
#include<stdio.h>
int main()
{
char p[] = "%d\n";
p[1] = 'c';
printf(p, 65);
return 0;
}
A.A
B.a
C.c
D.65
Answer: Option A
Explanation:Step 1: char p[] = "%d\n"; The variable p is declared as an array of characters and initialized with string "%d".
Step 2: p[1] = 'c'; Here, we overwrite the second element of array p by 'c'. So array p becomes "%c".
Step 3: printf(p, 65); becomes printf("%c", 65);
Therefore it prints the ASCII value of 65. The output is 'A'.
10.What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
printf("%d\n", strlen("123456"));
return 0;
}
A.6
B.12
C.7
D.2
Answer: Option A
Explanation:The function strlen returns the number of characters in the given string.
Therefore, strlen("123456") returns 6.
Hence the output of the program is "6".
11.What will be the output of the program ?
#include<stdio.h>
int main()
{
printf(5+"Good Morning\n");
return 0;
}
A.Good Morning
B.Good
C.M
D.Morning
12. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str[] = "India\0\BIX\0";
printf("%s\n", str);
return 0;
}
A.BIX
B.India
C.India BIX
D.India\0BIX
Answer: Option B
Explanation:A string is a collection of characters terminated by '\0'.
Step 1: char str[] = "India\0\BIX\0"; The variable str is declared as an array of characters and initialized with value "India"
Step 2: printf("%s\n", str); It prints the value of the str.
The output of the program is "India".
13. What will be the output of the program If characters 'a', 'b' and 'c' enter are supplied as input?
#include<stdio.h>
int main()
{
void fun();
fun();
printf("\n");
return 0;
}
void fun()
{
char c;
if((c = getchar())!= '\n')
fun();
printf("%c", c);
}
A.abc abc
B.bca
C.Infinite loop
D.cba
Answer: Option D
Explanation:Step 1: void fun(); This is the prototype for the function fun().
Step 2: fun(); The function fun() is called here.
The function fun() gets a character input and the input is terminated by an enter key(New line character). It prints the given character in the reverse order.
The given input characters are "abc"
Output: cba
14. What will be the output of the program ?
#include<stdio.h>
int main()
{
printf("India", "BIX\n");
return 0;
}
A.Error
B.India BIX
C.India
D.BIX
15. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[7] = "IndiaBIX";
printf("%s\n", str);
return 0;
}
A.Error
B.IndiaBIX
C.Cannot predict
D.None of above
Answer: Option C
Explanation:Here str[] has declared as 7 character array and into a 8 character is stored. This will result in overwriting of the byte beyond 7 byte reserved for '\0'.
16. What will be the output of the program ?
#include<stdio.h>
int main()
{
char *names[] = { "Suresh", "Siva", "Sona", "Baiju", "Ritu"};
int i;
char *t;
t = names[3];
names[3] = names[4];
names[4] = t;
for(i=0; i<=4; i++)
printf("%s,", names[i]);
return 0;
}
A.Suresh, Siva, Sona, Baiju, Ritu
B.Suresh, Siva, Sona, Ritu, Baiju
C.Suresh, Siva, Baiju, Sona, Ritu
D.Suresh, Siva, Ritu, Sona, Baiju
Answer: Option B
Explanation:Step 1: char *names[] = { "Suresh", "Siva", "Sona", "Baiju", "Ritu"}; The variable names is declared as an pointer to a array of strings.
Step 2: int i; The variable i is declared as an integer type.
Step 3: char *t; The variable t is declared as pointer to a string.
Step 4: t = names[3]; names[3] = names[4]; names[4] = t; These statements the swaps the 4 and 5 element of the array names.
Step 5: for(i=0; i<=4; i++) printf("%s,", names[i]); These statement prints the all the value of the array names.
Hence the output of the program is "Suresh, Siva, Sona, Ritu, Baiju".
17. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str[] = "India\0\BIX\0";
printf("%d\n", strlen(str));
return 0;
}
A.10
B.6
C.5
D.11
Answer: Option C
Explanation:The function strlen returns the number of characters int the given string.
Therefore, strlen(str) becomes strlen("India") contains 5 characters. A string is a collection of characters terminated by '\0'.
The output of the program is "5".
18. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
static char str1[] = "dills";
static char str2[20];
static char str3[] = "Daffo";
int i;
i = strcmp(strcat(str3, strcpy(str2, str1)), "Daffodills");
printf("%d\n", i);
return 0;
}
A.0
B.1
C.2
D.4
Answer: Option A
19. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
static char s[] = "Hello!";
printf("%d\n", *(s+strlen(s)));
return 0;
}
A.8
B.0
C.16
D.Error
Answer: Option B
20. What will be the output of the program ?
#include<stdio.h>
int main()
{
static char s[25] = "The cocaine man";
int i=0;
char ch;
ch = s[++i];
printf("%c", ch);
ch = s[i++];
printf("%c", ch);
ch = i++[s];
printf("%c", ch);
ch = ++i[s];
printf("%c", ch);
return 0;
}
A.hhe!
B.he c
C.The c
D.Hhec
Answer: Option A
21. What will be the output of the program in 16-bit platform (Turbo C under DOS) ?
#include<stdio.h>
int main()
{
printf("%d, %d, %d", sizeof(3.0f), sizeof('3'), sizeof(3.0));
return 0;
}
A.8, 1, 4
B.4, 2, 8
C.4, 2, 4
D.10, 3, 4
22. What will be the output of the program ?
#include<stdio.h>
int main()
{
int i;
char a[] = "\0";
if(printf("%s", a))
printf("The string is empty\n");
else
printf("The string is not empty\n");
return 0;
}
A.The string is empty
B.The string is not empty
C.No output
D.0
Answer: Option B
Explanation:The function printf() returns the number of charecters printed on the console.
Step 1: char a[] = "\0"; The variable a is declared as an array of characters and it initialized with "\0". It denotes that the string is empty.
Step 2: if(printf("%s", a)) The printf() statement does not print anything, so it returns '0'(zero). Hence the if condition is failed.
In the else part it prints "The string is not empty".
23. If char=1, int=4, and float=4 bytes size, What will be the output of the program ?
#include<stdio.h>
int main()
{
char ch = 'A';
printf("%d, %d, %d", sizeof(ch), sizeof('A'), sizeof(3.14f));
return 0;
}
A.1, 2, 4
B.1, 4, 4
C.2, 2, 4
D.2, 4, 8
Answer: Option B
Explanation:Step 1: char ch = 'A'; The variable ch is declared as an character type and initialized with value 'A'.
Step 2:
printf("%d, %d, %d", sizeof(ch), sizeof('A'), sizeof(3.14));
The sizeof function returns the size of the given expression.
sizeof(ch) becomes sizeof(char). The size of char is 1 byte.
sizeof('A') becomes sizeof(65). The size of int is 4 bytes (as mentioned in the question).
sizeof(3.14f). The size of float is 4 bytes.
Hence the output of the program is 1, 4, 4
24. If the size of pointer is 32 bits What will be the output of the program ?
#include<stdio.h>
int main()
{
char a[] = "Visual C++";
char *b = "Visual C++";
printf("%d, %d\n", sizeof(a), sizeof(b));
printf("%d, %d", sizeof(*a), sizeof(*b));
return 0;
}
A.10, 22, 2
B.10, 41, 2
C.11, 41, 1
D.12, 22, 2
Answer: Option C
25. What will be the output of the program ?
#include<stdio.h>
int main()
{
static char mess[6][30] = {"Don't walk in front of me...",
"I may not follow;",
"Don't walk behind me...",
"Just walk beside me...",
"And be my friend." };
printf("%c, %c\n", *(mess[2]+9), *(*(mess+2)+9));
return 0;
}
A.t, t
B.k, k
C.n, k
D.m, f
26. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str1[] = "Hello";
char str2[10];
char *t, *s;
s = str1;
t = str2;
while(*t=*s)
*t++ = *s++;
printf("%s\n", str2);
return 0;
}
A.Hello
B.HelloHello
C.No output
D.ello
Answer: Option A
27. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[] = "India\0BIX\0";
printf("%d\n", sizeof(str));
return 0;
}
A.10
B.6
C.5
D.11
Answer: Option D
Explanation:The following examples may help you understand this problem:
1. sizeof("") returns 1 (1*).
2. sizeof("India") returns 6 (5 + 1*).
3. sizeof("BIX") returns 4 (3 + 1*).
4. sizeof("India\0BIX") returns 10 (5 + 1 + 3 + 1*).
Here '\0' is considered as 1 char by sizeof() function.
5. sizeof("India\0BIX\0") returns 11 (5 + 1 + 3 + 1 + 1*).
Here '\0' is considered as 1 char by sizeof() function.
28. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[25] = "IndiaBIX";
printf("%s\n", &str+2);
return 0;
}
A.Garbage value
B.Error
C.No output
D.diaBIX
Answer: Option A
Explanation:Step 1: char str[25] = "IndiaBIX"; The variable str is declared as an array of characteres and initialized with a string "IndiaBIX".
Step 2: printf("%s\n", &str+2);
=> In the printf statement %s is string format specifier tells the compiler to print the string in the memory of &str+2
=> &str is a location of string "IndiaBIX". Therefore &str+2 is another memory location.
Hence it prints the Garbage value.
29. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str = "IndiaBIX";
printf("%s\n", str);
return 0;
}
A.Error
B.IndiaBIX
C.Base address of str
D.No output
Answer: Option A
Explanation:The line char str = "IndiaBIX"; generates "Non portable pointer conversion" error.
To eliminate the error, we have to change the above line to
char *str = "IndiaBIX"; (or) char str[] = "IndiaBIX";
Then it prints "IndiaBIX".
30. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[] = "Nagpur";
str[0]='K';
printf("%s, ", str);
str = "Kanpur";
printf("%s", str+1);
return 0;
}
A.Kagpur, Kanpur
B.Nagpur, Kanpur
C.Kagpur, anpur
D.Error
Answer: Option D
Explanation:The statement str = "Kanpur"; generates the LVALUE required error. We have to use strcpy function to copy a string.
To remove error we have to change this statement str = "Kanpur"; to strcpy(str, "Kanpur");
The program prints the string "anpur"
31. What will be the output of the program ?
#include<stdio.h>
int main()
{
printf(5+"IndiaBIX\n");
return 0;
}
A.Error
B.IndiaBIX
C.BIX
D.None of above
Answer: Option C
Explanation:printf(5+"IndiaBIX\n"); In the printf statement, it skips the first 5 characters and it prints "BIX"
32. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char sentence[80];
int i;
printf("Enter a line of text\n");
gets(sentence);
for(i=strlen(sentence)-1; i >=0; i--)
putchar(sentence[i]);
return 0;
}
A.The sentence will get printed in same order as it entered
B.The sentence will get printed in reverse order
C.Half of the sentence will get printed
D.None of above
Answer: Option B
33. What will be the output of the program ?
#include<stdio.h>
void swap(char *, char *);
int main()
{
char *pstr[2] = {"Hello", "IndiaBIX"};
swap(pstr[0], pstr[1]);
printf("%s\n%s", pstr[0], pstr[1]);
return 0;
}
void swap(char *t1, char *t2)
{
char *t;
t=t1;
t1=t2;
t2=t;
}
A.IndiaBIXHello
B.Address of "Hello" and "IndiaBIX"
C.HelloIndiaBIX
D.IelloHndiaBIX
Answer: Option C
Explanation:Step 1: void swap(char *, char *); This prototype tells the compiler that the function swap accept two strings as arguments and it does not return anything.
Step 2: char *pstr[2] = {"Hello", "IndiaBIX"}; The variable pstr is declared as an pointer to the array of strings. It is initialized to
pstr[0] = "Hello", pstr[1] = "IndiaBIX"
Step 3: swap(pstr[0], pstr[1]); The swap function is called by "call by value". Hence it does not affect the output of the program.
If the swap function is "called by reference" it will affect the variable pstr.
Step 4: printf("%s\n%s", pstr[0], pstr[1]); It prints the value of pstr[0] and pstr[1].
Hence the output of the program is
Hello
IndiaBIX
34. What will be the output of the program (Turbo C in 16 bit platform DOS) ?
#include<stdio.h>
#include<string.h>
int main()
{
char *str1 = "India";
char *str2 = "BIX";
char *str3;
str3 = strcat(str1, str2);
printf("%s %s\n", str3, str1);
return 0;
}
A.IndiaBIX India
B.IndiaBIX IndiaBIX
C.India India
D.Error
Answer: Option B
Explanation:It prints 'IndiaBIX IndiaBIX' in TurboC (in 16 bit platform).
It may cause a 'segmentation fault error' in GCC (32 bit platform).
35. If the size of pointer is 4 bytes then What will be the output of the program ?
#include<stdio.h>
int main()
{
char *str[] = {"Frogs", "Do", "Not", "Die", "They", "Croak!"};
printf("%d, %d", sizeof(str), strlen(str[0]));
return 0;
}
A.22, 4
B.25, 5
C.24, 5
D.20, 2
Answer: Option C
Explanation:Step 1: char *str[] = {"Frogs", "Do", "Not", "Die", "They", "Croak!"}; The variable str is declared as an pointer to the array of 6 strings.
Step 2: printf("%d, %d", sizeof(str), strlen(str[0]));
sizeof(str) denotes 6 * 4 bytes = 24 bytes. Hence it prints '24'
strlen(str[0])); becomes strlen(Frogs)). Hence it prints '5';
Hence the output of the program is 24, 5
Hint: If you run the above code in 16 bit platform (Turbo C under DOS) the output will be 12, 5. Because the pointer occupies only 2 bytes. If you run the above code in Linux (32 bit platform), the output will be 24, 5 (because the size of pointer is 4 bytes).
36. What will be the output of the program ?
#include<stdio.h>
int main()
{
int i;
char a[] = "\0";
if(printf("%s", a))
printf("The string is not empty\n");
else
printf("The string is empty\n");
return 0;
}
A.The string is not empty
B.The string is empty
C.No output
D.0
Answer: Option B
Explanation:The function printf() returns the number of charecters printed on the console.
Step 1: char a[] = '\0'; The variable a is declared as an array of characters and it initialized with "\0". It denotes that the string is empty.
Step 2: if(printf("%s", a)) The printf() statement does not print anything, so it returns '0'(zero). Hence the if condition is failed.
In the else part it prints "The string is empty".
37. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str1[5], str2[5];
int i;
gets(str1);
gets(str2);
i = strcmp(str1, str2);
printf("%d\n", i);
return 0;
}
A.Unpredictable integer value
B.0
C.-1
D.Error
Answer: Option A
Explanation:gets() gets collects a string of characters terminated by a new line from the standard input stream stdin.
The gets(str1) read the input string from user and store in variable str1.
The gets(str2) read the input string from user and store in variable str2.
The code i = strcmp(str1, str2); The strcmp not only returns -1, 0 and +1, but also other negative or positive values. So the value of i is "unpredictable integer value".
printf("%d\n", i); It prints the value of variable i.
38.What will be the output of the program in Turbo C?
#include<stdio.h>
int main()
{
char str[10] = "India";
str[6] = "BIX";
printf("%s\n", str);
return 0;
}
A.India BIX
B.BIX
C.India
D.Error
Answer: Option D
Explanation:str[6] = "BIX"; - Nonportable pointer conversion.
39. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str1[] = "Hello";
char str2[] = "Hello";
if(str1 == str2)
printf("Equal\n");
else
printf("Unequal\n");
return 0;
}
A.Equal
B.Unequal
C.Error
D.None of above
Answer: Option B
Explanation:Step 1: char str1[] = "Hello"; The variable str1 is declared as an array of characters and initialized with a string "Hello".
Step 2: char str2[] = "Hello"; The variable str2 is declared as an array of characters and initialized with a string "Hello".
We have use strcmp(s1,s2) function to compare strings.
Step 3: if(str1 == str2) here the address of str1 and str2 are compared. The address of both variable is not same. Hence the if condition is failed.
Step 4: At the else part it prints "Unequal".
40. What will be the output of the program ?
#include<stdio.h>
int main()
{
char t;
char *p1 = "India", *p2;
p2=p1;
p1 = "BIX";
printf("%s %s\n", p1, p2);
return 0;
}
A.India BIX
B.BIX India
C.India India
D.BIX BIX
Answer: Option B
Explanation:Step 1: char *p1 = "India", *p2; The variable p1 and p2 is declared as an pointer to a character value and p1 is assigned with a value "India".
Step 2: p2=p1; The value of p1 is assigned to variable p2. So p2 contains "India".
Step 3: p1 = "BIX"; The p1 is assigned with a string "BIX"
Step 4: printf("%s %s\n", p1, p2); It prints the value of p1 and p2.
Hence the output of the program is "BIX India".
41. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
printf("%c\n", "abcdefgh"[4]);
return 0;
}
A.Error
B.d
C.e
D.abcdefgh
Answer: Option C
Explanation:printf("%c\n", "abcdefgh"[4]); It prints the 5 character of the string "abcdefgh".
Hence the output is 'e'.
42. What will be the output of the following program in 16 bit platform assuming that 1022 is memory address of the string "Hello1" (in Turbo C under DOS) ?
#include<stdio.h>
int main()
{
printf("%u %s\n", &"Hello1", &"Hello2");
return 0;
}
A.1022 Hello2
B.Hello1 1022
C.Hello1 Hello2
D.1022 1022
E.Error
Answer: Option A
Explanation:In printf("%u %s\n", &"Hello", &"Hello");.
The %u format specifier tells the compiler to print the memory address of the "Hello1".
The %s format specifier tells the compiler to print the string "Hello2".
Hence the output of the program is "1022 Hello2".
1. Which of the following function sets first n characters of a string to a given character?
A.strinit()
B.strnset()
C.strset()
D.strcset()
Answer: Option B
Explanation:char *strnset(char *s, int ch, size_t n); Sets the first n characters of s to ch
#include <stdio.h>
#include <string.h>
int main(void)
{
char *string = "abcdefghijklmnopqrstuvwxyz";
char letter = 'x';
printf("string before strnset: %s\n", string);
strnset(string, letter, 13);
printf("string after strnset: %s\n", string);
return 0;
}
Output:
string before strnset: abcdefghijklmnopqrstuvwxyz
string after strnset: xxxxxxxxxxxxxnopqrstuvwxyz
2. If the two strings are identical, then strcmp() function returns
A.-1
B.1
C.0
D.Yes
3. How will you print \n on the screen?
A.printf("\n");
B.echo "\\n";
C.printf('\n');
D.printf("\\n");
Answer: Option D
Explanation:The statement printf("\\n"); prints '\n' on the screen.
4. The library function used to find the last occurrence of a character in a string is
A.strnstr()
B.laststr()
C.strrchr()
D.strstr()
5. Which of the following function is used to find the first occurrence of a given string in another string?
A.strchr()
B.strrchr()
C.strstr()
D.strnset()
Answer: Option C
Explanation:The function strstr() Finds the first occurrence of a substring in another string
Declaration: char *strstr(const char *s1, const char *s2);
Return Value:
On success, strstr returns a pointer to the element in s1 where s2 begins (points to s2 in s1).
On error (if s2 does not occur in s1), strstr returns null.
Example:
#include <stdio.h>
#include <string.h>
int main(void)
{
char *str1 = "IndiaBIX", *str2 = "ia", *ptr;
ptr = strstr(str1, str2);
printf("The substring is: %s\n", ptr);
return 0;
}
Output: The substring is: iaBIX
6. Which of the following function is more appropriate for reading in a multi-word string?
A.printf();
B.scanf();
C.gets();
D.puts();
Answer: Option C
Explanation:gets(); collects a string of characters terminated by a new line from the standard input stream stdin
#include <stdio.h>
int main(void)
{
char string[80];
printf("Enter a string:");
gets(string);
printf("The string input was: %s\n", string);
return 0;
}
Output:
Enter a string: IndiaBIX
The string input was: IndiaBIX
7. Which of the following function is correct that finds the length of a string?
A.int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
{ length++; s++; }
return (length);
}
B.int xstrlen(char s)
{
int length=0;
while(*s!='\0')
length++; s++;
return (length);
}
C.int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
length++;
return (length);
}
D.int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
s++;
return (length);
}
Answer: Option A
Explanation:option A is the correct function to find the length of given string.
Example:
#include<stdio.h>
int xstrlen(char *s)
{
int length=0;
while(*s!='\0')
{ length++; s++; }
return (length);
}
int main()
{
char d[] = "IndiaBIX";
printf("Length = %d\n", xstrlen(d));
return 0;
}
Output: Length = 8
8.What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str1[20] = "Hello", str2[20] = " World";
printf("%s\n", strcpy(str2, strcat(str1, str2)));
return 0;
}
A.Hello
B.World
C.Hello World
D.WorldHello
Answer: Option C
Explanation:Step 1: char str1[20] = "Hello", str2[20] = " World"; The variable str1 and str2 is declared as an array of characters and initialized with value "Hello" and " World" respectively.
Step 2: printf("%s\n", strcpy(str2, strcat(str1, str2)));
=> strcat(str1, str2)) it append the string str2 to str1. The result will be stored in str1. Therefore str1 contains "Hello World".
=> strcpy(str2, "Hello World") it copies the "Hello World" to the variable str2.
Hence it prints "Hello World".
9. What will be the output of the program ?
#include<stdio.h>
int main()
{
char p[] = "%d\n";
p[1] = 'c';
printf(p, 65);
return 0;
}
A.A
B.a
C.c
D.65
Answer: Option A
Explanation:Step 1: char p[] = "%d\n"; The variable p is declared as an array of characters and initialized with string "%d".
Step 2: p[1] = 'c'; Here, we overwrite the second element of array p by 'c'. So array p becomes "%c".
Step 3: printf(p, 65); becomes printf("%c", 65);
Therefore it prints the ASCII value of 65. The output is 'A'.
10.What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
printf("%d\n", strlen("123456"));
return 0;
}
A.6
B.12
C.7
D.2
Answer: Option A
Explanation:The function strlen returns the number of characters in the given string.
Therefore, strlen("123456") returns 6.
Hence the output of the program is "6".
11.What will be the output of the program ?
#include<stdio.h>
int main()
{
printf(5+"Good Morning\n");
return 0;
}
A.Good Morning
B.Good
C.M
D.Morning
12. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str[] = "India\0\BIX\0";
printf("%s\n", str);
return 0;
}
A.BIX
B.India
C.India BIX
D.India\0BIX
Answer: Option B
Explanation:A string is a collection of characters terminated by '\0'.
Step 1: char str[] = "India\0\BIX\0"; The variable str is declared as an array of characters and initialized with value "India"
Step 2: printf("%s\n", str); It prints the value of the str.
The output of the program is "India".
13. What will be the output of the program If characters 'a', 'b' and 'c' enter are supplied as input?
#include<stdio.h>
int main()
{
void fun();
fun();
printf("\n");
return 0;
}
void fun()
{
char c;
if((c = getchar())!= '\n')
fun();
printf("%c", c);
}
A.abc abc
B.bca
C.Infinite loop
D.cba
Answer: Option D
Explanation:Step 1: void fun(); This is the prototype for the function fun().
Step 2: fun(); The function fun() is called here.
The function fun() gets a character input and the input is terminated by an enter key(New line character). It prints the given character in the reverse order.
The given input characters are "abc"
Output: cba
14. What will be the output of the program ?
#include<stdio.h>
int main()
{
printf("India", "BIX\n");
return 0;
}
A.Error
B.India BIX
C.India
D.BIX
15. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[7] = "IndiaBIX";
printf("%s\n", str);
return 0;
}
A.Error
B.IndiaBIX
C.Cannot predict
D.None of above
Answer: Option C
Explanation:Here str[] has declared as 7 character array and into a 8 character is stored. This will result in overwriting of the byte beyond 7 byte reserved for '\0'.
16. What will be the output of the program ?
#include<stdio.h>
int main()
{
char *names[] = { "Suresh", "Siva", "Sona", "Baiju", "Ritu"};
int i;
char *t;
t = names[3];
names[3] = names[4];
names[4] = t;
for(i=0; i<=4; i++)
printf("%s,", names[i]);
return 0;
}
A.Suresh, Siva, Sona, Baiju, Ritu
B.Suresh, Siva, Sona, Ritu, Baiju
C.Suresh, Siva, Baiju, Sona, Ritu
D.Suresh, Siva, Ritu, Sona, Baiju
Answer: Option B
Explanation:Step 1: char *names[] = { "Suresh", "Siva", "Sona", "Baiju", "Ritu"}; The variable names is declared as an pointer to a array of strings.
Step 2: int i; The variable i is declared as an integer type.
Step 3: char *t; The variable t is declared as pointer to a string.
Step 4: t = names[3]; names[3] = names[4]; names[4] = t; These statements the swaps the 4 and 5 element of the array names.
Step 5: for(i=0; i<=4; i++) printf("%s,", names[i]); These statement prints the all the value of the array names.
Hence the output of the program is "Suresh, Siva, Sona, Ritu, Baiju".
17. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str[] = "India\0\BIX\0";
printf("%d\n", strlen(str));
return 0;
}
A.10
B.6
C.5
D.11
Answer: Option C
Explanation:The function strlen returns the number of characters int the given string.
Therefore, strlen(str) becomes strlen("India") contains 5 characters. A string is a collection of characters terminated by '\0'.
The output of the program is "5".
18. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
static char str1[] = "dills";
static char str2[20];
static char str3[] = "Daffo";
int i;
i = strcmp(strcat(str3, strcpy(str2, str1)), "Daffodills");
printf("%d\n", i);
return 0;
}
A.0
B.1
C.2
D.4
Answer: Option A
19. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
static char s[] = "Hello!";
printf("%d\n", *(s+strlen(s)));
return 0;
}
A.8
B.0
C.16
D.Error
Answer: Option B
20. What will be the output of the program ?
#include<stdio.h>
int main()
{
static char s[25] = "The cocaine man";
int i=0;
char ch;
ch = s[++i];
printf("%c", ch);
ch = s[i++];
printf("%c", ch);
ch = i++[s];
printf("%c", ch);
ch = ++i[s];
printf("%c", ch);
return 0;
}
A.hhe!
B.he c
C.The c
D.Hhec
Answer: Option A
21. What will be the output of the program in 16-bit platform (Turbo C under DOS) ?
#include<stdio.h>
int main()
{
printf("%d, %d, %d", sizeof(3.0f), sizeof('3'), sizeof(3.0));
return 0;
}
A.8, 1, 4
B.4, 2, 8
C.4, 2, 4
D.10, 3, 4
22. What will be the output of the program ?
#include<stdio.h>
int main()
{
int i;
char a[] = "\0";
if(printf("%s", a))
printf("The string is empty\n");
else
printf("The string is not empty\n");
return 0;
}
A.The string is empty
B.The string is not empty
C.No output
D.0
Answer: Option B
Explanation:The function printf() returns the number of charecters printed on the console.
Step 1: char a[] = "\0"; The variable a is declared as an array of characters and it initialized with "\0". It denotes that the string is empty.
Step 2: if(printf("%s", a)) The printf() statement does not print anything, so it returns '0'(zero). Hence the if condition is failed.
In the else part it prints "The string is not empty".
23. If char=1, int=4, and float=4 bytes size, What will be the output of the program ?
#include<stdio.h>
int main()
{
char ch = 'A';
printf("%d, %d, %d", sizeof(ch), sizeof('A'), sizeof(3.14f));
return 0;
}
A.1, 2, 4
B.1, 4, 4
C.2, 2, 4
D.2, 4, 8
Answer: Option B
Explanation:Step 1: char ch = 'A'; The variable ch is declared as an character type and initialized with value 'A'.
Step 2:
printf("%d, %d, %d", sizeof(ch), sizeof('A'), sizeof(3.14));
The sizeof function returns the size of the given expression.
sizeof(ch) becomes sizeof(char). The size of char is 1 byte.
sizeof('A') becomes sizeof(65). The size of int is 4 bytes (as mentioned in the question).
sizeof(3.14f). The size of float is 4 bytes.
Hence the output of the program is 1, 4, 4
24. If the size of pointer is 32 bits What will be the output of the program ?
#include<stdio.h>
int main()
{
char a[] = "Visual C++";
char *b = "Visual C++";
printf("%d, %d\n", sizeof(a), sizeof(b));
printf("%d, %d", sizeof(*a), sizeof(*b));
return 0;
}
A.10, 22, 2
B.10, 41, 2
C.11, 41, 1
D.12, 22, 2
Answer: Option C
25. What will be the output of the program ?
#include<stdio.h>
int main()
{
static char mess[6][30] = {"Don't walk in front of me...",
"I may not follow;",
"Don't walk behind me...",
"Just walk beside me...",
"And be my friend." };
printf("%c, %c\n", *(mess[2]+9), *(*(mess+2)+9));
return 0;
}
A.t, t
B.k, k
C.n, k
D.m, f
26. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str1[] = "Hello";
char str2[10];
char *t, *s;
s = str1;
t = str2;
while(*t=*s)
*t++ = *s++;
printf("%s\n", str2);
return 0;
}
A.Hello
B.HelloHello
C.No output
D.ello
Answer: Option A
27. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[] = "India\0BIX\0";
printf("%d\n", sizeof(str));
return 0;
}
A.10
B.6
C.5
D.11
Answer: Option D
Explanation:The following examples may help you understand this problem:
1. sizeof("") returns 1 (1*).
2. sizeof("India") returns 6 (5 + 1*).
3. sizeof("BIX") returns 4 (3 + 1*).
4. sizeof("India\0BIX") returns 10 (5 + 1 + 3 + 1*).
Here '\0' is considered as 1 char by sizeof() function.
5. sizeof("India\0BIX\0") returns 11 (5 + 1 + 3 + 1 + 1*).
Here '\0' is considered as 1 char by sizeof() function.
28. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[25] = "IndiaBIX";
printf("%s\n", &str+2);
return 0;
}
A.Garbage value
B.Error
C.No output
D.diaBIX
Answer: Option A
Explanation:Step 1: char str[25] = "IndiaBIX"; The variable str is declared as an array of characteres and initialized with a string "IndiaBIX".
Step 2: printf("%s\n", &str+2);
=> In the printf statement %s is string format specifier tells the compiler to print the string in the memory of &str+2
=> &str is a location of string "IndiaBIX". Therefore &str+2 is another memory location.
Hence it prints the Garbage value.
29. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str = "IndiaBIX";
printf("%s\n", str);
return 0;
}
A.Error
B.IndiaBIX
C.Base address of str
D.No output
Answer: Option A
Explanation:The line char str = "IndiaBIX"; generates "Non portable pointer conversion" error.
To eliminate the error, we have to change the above line to
char *str = "IndiaBIX"; (or) char str[] = "IndiaBIX";
Then it prints "IndiaBIX".
30. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str[] = "Nagpur";
str[0]='K';
printf("%s, ", str);
str = "Kanpur";
printf("%s", str+1);
return 0;
}
A.Kagpur, Kanpur
B.Nagpur, Kanpur
C.Kagpur, anpur
D.Error
Answer: Option D
Explanation:The statement str = "Kanpur"; generates the LVALUE required error. We have to use strcpy function to copy a string.
To remove error we have to change this statement str = "Kanpur"; to strcpy(str, "Kanpur");
The program prints the string "anpur"
31. What will be the output of the program ?
#include<stdio.h>
int main()
{
printf(5+"IndiaBIX\n");
return 0;
}
A.Error
B.IndiaBIX
C.BIX
D.None of above
Answer: Option C
Explanation:printf(5+"IndiaBIX\n"); In the printf statement, it skips the first 5 characters and it prints "BIX"
32. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char sentence[80];
int i;
printf("Enter a line of text\n");
gets(sentence);
for(i=strlen(sentence)-1; i >=0; i--)
putchar(sentence[i]);
return 0;
}
A.The sentence will get printed in same order as it entered
B.The sentence will get printed in reverse order
C.Half of the sentence will get printed
D.None of above
Answer: Option B
33. What will be the output of the program ?
#include<stdio.h>
void swap(char *, char *);
int main()
{
char *pstr[2] = {"Hello", "IndiaBIX"};
swap(pstr[0], pstr[1]);
printf("%s\n%s", pstr[0], pstr[1]);
return 0;
}
void swap(char *t1, char *t2)
{
char *t;
t=t1;
t1=t2;
t2=t;
}
A.IndiaBIXHello
B.Address of "Hello" and "IndiaBIX"
C.HelloIndiaBIX
D.IelloHndiaBIX
Answer: Option C
Explanation:Step 1: void swap(char *, char *); This prototype tells the compiler that the function swap accept two strings as arguments and it does not return anything.
Step 2: char *pstr[2] = {"Hello", "IndiaBIX"}; The variable pstr is declared as an pointer to the array of strings. It is initialized to
pstr[0] = "Hello", pstr[1] = "IndiaBIX"
Step 3: swap(pstr[0], pstr[1]); The swap function is called by "call by value". Hence it does not affect the output of the program.
If the swap function is "called by reference" it will affect the variable pstr.
Step 4: printf("%s\n%s", pstr[0], pstr[1]); It prints the value of pstr[0] and pstr[1].
Hence the output of the program is
Hello
IndiaBIX
34. What will be the output of the program (Turbo C in 16 bit platform DOS) ?
#include<stdio.h>
#include<string.h>
int main()
{
char *str1 = "India";
char *str2 = "BIX";
char *str3;
str3 = strcat(str1, str2);
printf("%s %s\n", str3, str1);
return 0;
}
A.IndiaBIX India
B.IndiaBIX IndiaBIX
C.India India
D.Error
Answer: Option B
Explanation:It prints 'IndiaBIX IndiaBIX' in TurboC (in 16 bit platform).
It may cause a 'segmentation fault error' in GCC (32 bit platform).
35. If the size of pointer is 4 bytes then What will be the output of the program ?
#include<stdio.h>
int main()
{
char *str[] = {"Frogs", "Do", "Not", "Die", "They", "Croak!"};
printf("%d, %d", sizeof(str), strlen(str[0]));
return 0;
}
A.22, 4
B.25, 5
C.24, 5
D.20, 2
Answer: Option C
Explanation:Step 1: char *str[] = {"Frogs", "Do", "Not", "Die", "They", "Croak!"}; The variable str is declared as an pointer to the array of 6 strings.
Step 2: printf("%d, %d", sizeof(str), strlen(str[0]));
sizeof(str) denotes 6 * 4 bytes = 24 bytes. Hence it prints '24'
strlen(str[0])); becomes strlen(Frogs)). Hence it prints '5';
Hence the output of the program is 24, 5
Hint: If you run the above code in 16 bit platform (Turbo C under DOS) the output will be 12, 5. Because the pointer occupies only 2 bytes. If you run the above code in Linux (32 bit platform), the output will be 24, 5 (because the size of pointer is 4 bytes).
36. What will be the output of the program ?
#include<stdio.h>
int main()
{
int i;
char a[] = "\0";
if(printf("%s", a))
printf("The string is not empty\n");
else
printf("The string is empty\n");
return 0;
}
A.The string is not empty
B.The string is empty
C.No output
D.0
Answer: Option B
Explanation:The function printf() returns the number of charecters printed on the console.
Step 1: char a[] = '\0'; The variable a is declared as an array of characters and it initialized with "\0". It denotes that the string is empty.
Step 2: if(printf("%s", a)) The printf() statement does not print anything, so it returns '0'(zero). Hence the if condition is failed.
In the else part it prints "The string is empty".
37. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
char str1[5], str2[5];
int i;
gets(str1);
gets(str2);
i = strcmp(str1, str2);
printf("%d\n", i);
return 0;
}
A.Unpredictable integer value
B.0
C.-1
D.Error
Answer: Option A
Explanation:gets() gets collects a string of characters terminated by a new line from the standard input stream stdin.
The gets(str1) read the input string from user and store in variable str1.
The gets(str2) read the input string from user and store in variable str2.
The code i = strcmp(str1, str2); The strcmp not only returns -1, 0 and +1, but also other negative or positive values. So the value of i is "unpredictable integer value".
printf("%d\n", i); It prints the value of variable i.
38.What will be the output of the program in Turbo C?
#include<stdio.h>
int main()
{
char str[10] = "India";
str[6] = "BIX";
printf("%s\n", str);
return 0;
}
A.India BIX
B.BIX
C.India
D.Error
Answer: Option D
Explanation:str[6] = "BIX"; - Nonportable pointer conversion.
39. What will be the output of the program ?
#include<stdio.h>
int main()
{
char str1[] = "Hello";
char str2[] = "Hello";
if(str1 == str2)
printf("Equal\n");
else
printf("Unequal\n");
return 0;
}
A.Equal
B.Unequal
C.Error
D.None of above
Answer: Option B
Explanation:Step 1: char str1[] = "Hello"; The variable str1 is declared as an array of characters and initialized with a string "Hello".
Step 2: char str2[] = "Hello"; The variable str2 is declared as an array of characters and initialized with a string "Hello".
We have use strcmp(s1,s2) function to compare strings.
Step 3: if(str1 == str2) here the address of str1 and str2 are compared. The address of both variable is not same. Hence the if condition is failed.
Step 4: At the else part it prints "Unequal".
40. What will be the output of the program ?
#include<stdio.h>
int main()
{
char t;
char *p1 = "India", *p2;
p2=p1;
p1 = "BIX";
printf("%s %s\n", p1, p2);
return 0;
}
A.India BIX
B.BIX India
C.India India
D.BIX BIX
Answer: Option B
Explanation:Step 1: char *p1 = "India", *p2; The variable p1 and p2 is declared as an pointer to a character value and p1 is assigned with a value "India".
Step 2: p2=p1; The value of p1 is assigned to variable p2. So p2 contains "India".
Step 3: p1 = "BIX"; The p1 is assigned with a string "BIX"
Step 4: printf("%s %s\n", p1, p2); It prints the value of p1 and p2.
Hence the output of the program is "BIX India".
41. What will be the output of the program ?
#include<stdio.h>
#include<string.h>
int main()
{
printf("%c\n", "abcdefgh"[4]);
return 0;
}
A.Error
B.d
C.e
D.abcdefgh
Answer: Option C
Explanation:printf("%c\n", "abcdefgh"[4]); It prints the 5 character of the string "abcdefgh".
Hence the output is 'e'.
42. What will be the output of the following program in 16 bit platform assuming that 1022 is memory address of the string "Hello1" (in Turbo C under DOS) ?
#include<stdio.h>
int main()
{
printf("%u %s\n", &"Hello1", &"Hello2");
return 0;
}
A.1022 Hello2
B.Hello1 1022
C.Hello1 Hello2
D.1022 1022
E.Error
Answer: Option A
Explanation:In printf("%u %s\n", &"Hello", &"Hello");.
The %u format specifier tells the compiler to print the memory address of the "Hello1".
The %s format specifier tells the compiler to print the string "Hello2".
Hence the output of the program is "1022 Hello2".
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