C Reference String Operation: strlen()

The strlen() function returns the length of a string.

The length is determined by the number of characters before the null termination.

Usage:

size_t strlen(char *str)

strlen() source code example:

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

	main()
	{
		char line[100];
		strcpy(line, "hello");

		printf ("%d\n", strlen(line));
	}

Output of the example:

	5