how to use strlen function in c++ code example

Example 1: c++ length of char*

#include <iostream>
#include <string.h>

using namespace std;

int main()
{
    char *str = "ABC";
    cout << strlen(str) << endl;
    return 0;
}

Example 2: strlen in cpp

#include <cstring>
#include <iostream>

using namespace std;

int main()
{
    char str1[] = "This a string";
    
    int len1 = strlen(str1);

    cout << "Length of str1 = " << len1 << endl;

    return 0;
}