How to get the Length of a String in C

In this post, we'll learn how to get the length of a string in C.

Thankfully, C provides us with a function called strlen() that does exactly what we need. The function is included with the standard library, inside the <string.h> header file.

First, let's define a string. Remember that a string in C is just an array of characters.

	char greeting[] = "Hello, world!";

Now, let's get the length of the string:

	char greeting[] = "Hello, world!";

int length = strlen(greeting);

Then if you want, you can print the length using printf:

	char greeting[] = "Hello, world!";

int length = strlen(greeting);

printf("greeting length: %u", length);

Here's a fully-working example:

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

int main(int argc, char *argv[]) {
    char greeting[] = "Hello, world!";

    int length = strlen(greeting);

    printf("greeting length: %u", length);
}

That's pretty much it. Now that you know how to get the length of a string, you can use that information however you want.