size of array of char 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: how to find the size of a character array in c++

Instead of sizeof() for finding the length of strings or character 
arrays, just use strlen(string_name) with the header file
#include <cstring>   
it's easier.