Pointer / Reference : C++

#include <iostream>
#include <string>

using namespace std;

// Class
class Swap{
    public:
    void jason(int x);
};

void Swap::jason(int x){
    //x = 200;
    cout << "Jason_val = " << x << endl ;
}

// Function without Class
void lee(int y);

void lee(int y){
    y = 200;
    cout << "Lee_val = " << y << endl ;
}

// Main Function
int main(void){
    string val = 20;

    cout << "Origin_val = " << val << endl;

    Swap sp;
    sp.jason(10);

    lee(100);

    cout << "InMain_val = " << val << endl;

    return 0;
}