初学c++模板，这个错误怎么改啊？

 [Error] call of overloaded 'swap(int&, int&)' is ambiguous

 [Error] call of overloaded 'swap(double&, double&)' is ambiguous

 [Error] call of overloaded 'swap(char&, char&)' is ambiguous

#include <iostream>
using namespace std;
template<typename A>
void swap(A a,A b){
	cout<<"a="<<a<<"b="<<b;
	A t;
	t=a;
	a=b;  b=t;
	cout<<"a="<<a<<"b="<<b;
}
int main() {
	int a=23,b=99;
	swap(a,b);
	double c=3.22222,d=8.666666;
	swap(c,d);
	char e='x',f='y';
	swap(e,f);
	return 0;
}

知道了