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// compile with: g++ hello.cpp
#include<iostream>
#include<string>
#include<vector>
using namespace std;
// function prototype, & means "pass by reference" - value will be copied back out
// note: just typing & once is less typing, but also if you just look at main you
//   won't know if swap actually changes x and y
void swap(int &a, int &b) {
  int temp = a;
  a = b;
  b = temp;
}
int main(int argc, char * argv[]) {
  cout << "x: "; int x; cin >> x;
  cout << "y: "; int y; cin >> y;
  cout << "swapping..." << endl;
  
  swap(x, y);
  cout << "x: " << x << endl;
  cout << "y: " << y << endl;
  
  return 0;
}
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