How to find the length of a string in C language?

In C language, we can use the strlen function to calculate the length of a string. This function is defined in the header file.

Here is how to use it:

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

int main() {
    char str[] = "Hello, World!";
    int len = strlen(str);
    printf("字符串的长度是：%d\n", len);
    return 0;
}

The output will be:

字符串的长度是：13

Please note that the function strlen returns a value of type unsigned int, representing the length of a string.