strlen

 

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Defined in header <string.h>
size_t strlen( const char *str );

Returns the length of the given byte string.

Parameters

str

-

pointer to the null-terminated byte string to be examined

Return value

The length of the null-terminated string str.

Example

run this code

#include <string.h>
#include <stdio.h>
 
int main()
{
   const char str[] = "How many characters contains this string?";
 
   printf("without null character: %d\n", strlen(str));
   printf("with null character: %d\n", sizeof(str));
 
   return 0;
}

Output:

without null character: 41
with null character: 42