demo of pass-by-value vs pass-by-reference in C++

pass-by-ref.cpp

#include <iostream>
#include <string>

using std::string;

void passByVal(string passBy) {
    passBy = "reference";
}

void passByRef(string &passBy) {
    passBy = "reference";
}

int main(int argc, char **argv) {
    {
    	string passBy = "value";
    	passByVal(passBy);
    	std::cout << "passByVal is pass-by-" << passBy << std::endl;
    }
    {
    	string passBy = "value";
    	passByRef(passBy);
    	std::cout << "passByRef is pass-by-" << passBy << std::endl;
    }
    return 0;
}