What are string searching functions in C language?

The library also provides several string searching functions, which are as follows −

char strchr (const char string, intc);	Find first occurrence of character c in string.
char "strrchr (const char "string, intc);	Find last occurrence of character c in string.
char strpbrk (const char s1,const char *s2);	returns a pointer to the first occurrence in string s1 of any character from string s2, or a null pointer if no character from s2 exists in s1.
size_t strspn (const char s1, const char s2);	returns the number of characters at the beginning of s1 that match s2.
size_t strcspn (const char 51, const char s2);	returns the number of characters at the beginning of s1 that do not match s2.
char strtok (char s1,const char *s2);	break the string pointed to by si into a sequence of tokens, each of which is delimited by one or more characters from the string pointed to by s2.
char strtok_r (char s1,const char *s2, char	has the same functionality as strtok () except**lasts); that a pointer to a string placeholder lasts must be supplied by the caller.

strchr () and strrchr () are the simplest to use.

Example 1

Following is the C program for the string searching functions −

#include <string.h>
#include <stdio.h>
void main(){
   char *str1 = "Hello";
   char *ans;
   ans = strchr (str1,'l');
   printf("%s\n", ans);
}

When the above program is executed, it produces the following result −

llo

After this execution, ans points to the location str1 + 2.

strpbrk () is a more general function that searches for the first occurrence of any of a group of characters.

Following is the C program for the use of strpbrk () function −

#include <string.h>
#include <stdio.h>
void main(){
   char *str1 = "Hello";
   char *ans;
   ans = strpbrk (str1,"aeiou");
   printf("%s\n",ans);
}

When the above program is executed, it produces the following result −

ello

Here, ans points to the location str1 + 1, the location of the first e.