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:

Declaration:

char *strnset(char *s, int ch, size_t n); Sets the first n characters of s to ch

#include
#include

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
Answer: Option C

Explanation:

Declaration: strcmp(const char *s1, const char*s2);

The strcmp return an int value that is

if s1 < s2 returns a value < 0 if s1 == s2 returns 0 if s1 > s2 returns a value > 0

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()
Answer: Option C

Explanation:

Declaration: char *strrchr(const char *s, int c);

It scans a string s in the reverse direction, looking for a specific character c.

Example:

#include
#include

int main(void)
{
char text[] = “I learn through IndiaBIX.com”;
char *ptr, c = ‘i’;

ptr = strrchr(text, c);
if (ptr)
printf(“The position of ‘%c’ is: %d\n”, c, ptr-text);
else
printf(“The character was not found\n”);
return 0;
}
Output:

The position of ‘i’ is: 19

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
#include

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