length function in c code example

Example 1: string length c

#include <stdio.h>
#include <string.h>
int main()
{
    char a[20]="Program";
    char b[20]={'P','r','o','g','r','a','m','\0'};

    // using the %zu format specifier to print size_t
    printf("Length of string a = %zu \n",strlen(a));
    printf("Length of string b = %zu \n",strlen(b));

    return 0;
}

Example 2: strlen return

>> strlen(buffer) function shall return the length of buffer excluding null termination;
    no return value shall be reserved to indicate an error.