参照　swap

#include < iostream >
using namespace std;

void swapargs(int &x, int &y);

int main()
{
    int i, j;
    
    i = 10;
    j = 19;
    
    cout << "i: " << i << ", ";
    cout << "j: " << j << "\n";
    
    swapargs(i, j);
    
    cout << "after exchange: ";
    cout << "i: " << i << ", ";
    cout << "j: " << j << "\n";
    
    return 0;
}

void swapargs(int &x, int &y)
{
    int t;
    
    t = x;
    x = y;
    y = t;
}