The **`strlen()`** function in C is used to calculate the length of a string. 

>Note: `strlen()` calculates the length of a string up to, but not including, the terminating null character.

Return Value: The function returns the length of the string passed to it.


# Syntax


The following is the syntax of the `strlen()` function:

# Example 1

The following example takes a simple string `string1` and calculates its length.

#include<stdio.h>
#include<string.h>
int main() {
  int len1;
  char string1[] = "Hello World!";
  len1 = strlen(string1);
  printf("Length of string1 is: %d \n", len1);
}

## Explanation

- The `strlen()` function from the string.h library is used to calculate the length of the string stored in `string1`. This length is then assigned to the variable `len1`.





#include<stdio.h>
#include<string.h>
int main() {
  int len2;
  char string2[] = {'c','o','m','p','u','t','e','r','\0'};
  len2 = strlen(string2);
  printf("Length of string2 is: %d \n", len2);
}

How to use the strlen() function in C

The strlen() function in C is used to calculate the length of a string.  Note: strlen() calculates the length of a string up to, but not including, the terminating null character.  Return Value: The function returns the length of the string passed to it. 

How to use the strlen() function in C

Syntax

Example 1

Explanation

Example 2

Code

Explanation