用指针来写：

void swap(int* x,int* y)
{
	int temp;
	temp=*y;
	*y=*x;
	*x=temp;

}

int main()
{
	int a,b;
	int* pa=&a;
	int* pb=&b;
	cout<<"请输入两个整数"<<endl;
	cin>>a>>b;
	cout<<"a="<<a<<" "<<"b="<<b<<endl;
	swap(pa,pb);
	cout<<"a="<<a<<" "<<"b="<<b<<endl;
	return 0;
}

用引用来写

void swap( int &x,int &y)
{
	int temp;
	temp=y;
	y=x;
	x=temp;
}
int main()
{
	int a,b;
	cout<<"请输入两个整数"<<endl;
	cin>>a>>b;
	cout<<"a="<<a<<" "<<"b="<<b<<endl;
	int &refa=a;
	int &refb=b;       //引用也需要定义
	swap(refa,refb);
	cout<<"a="<<a<<" "<<"b="<<b<<endl;
	return 0;
}