#include<iostream>
using namespace std;

void badSwap(int a,int b){
	int c=a;
	a=b;
	b=c;
}
void goodSwap(int& a,int& b){
	int c=a;
	a=b;
	b=c;
}
void pointerSwap(int* a,int* b){
	int c=(*a);
	(*a)=(*b);
	(*b)=c;
}
int main()
{
	int a=1,b=2;
	badSwap(a,b);
	cout<<a<<" "<<b<<endl;
	goodSwap(a,b);
	cout<<a<<" "<<b<<endl;
	pointerSwap(&a,&b);
	cout<<a<<" "<<b<<endl;
	return 0;
}
/* OUTPUT :
1 2
2 1
1 2
*/