Comparing strings in the C language to determine if they are equal.

In C language, you can use the strcmp function to compare if two strings are equal. The prototype of the strcmp function is as follows:

int strcmp(const char *str1, const char *str2);

The function takes two parameters, which are the two strings to be compared. If the two strings are equal, the return value is 0; if str1 is less than str2, the return value is less than 0; if str1 is greater than str2, the return value is greater than 0. Here is an example code:

#include <stdio.h>
#include <string.h>

int main() {
    char str1[] = "Hello";
    char str2[] = "Hello";
    char str3[] = "Hi";

    if (strcmp(str1, str2) == 0) {
        printf("str1 and str2 are equal.\n");
    } else {
        printf("str1 and str2 are not equal.\n");
    }

    if (strcmp(str1, str3) == 0) {
        printf("str1 and str3 are equal.\n");
    } else {
        printf("str1 and str3 are not equal.\n");
    }

    return 0;
}

When running the code above, the output will be as follows:

str1 and str2 are equal.
str1 and str3 are not equal.