Use of strstr in C

strstr in C

strstr is a function in C that is used to find the first occurrence of a substring in a string. It is declared in the <string.h> header.

Syntax:

char *strstr(const char *str1, const char *str2);

• str1 → The main string in which you want to search.
• str2→ The substring you are searching for.

Returns:

• A pointer to the first occurrence of str2 in str1.
• NULL if str2 is not found.

Example:

#include <stdio.h>

#include <string.h>

int main() {

    char str[] = "Hello, welcome to C programming!";

    char substr[] = "welcome";

    // Using strstr to find substring

    char *result = strstr(str, substr);

    if (result != NULL) {

        printf("Substring found at position: %ld\n", result - str);

    } else {

        printf("Substring not found.\n");

    }

    return 0;

}

Output:

Substring found at position: 7