模版实例化

#include <iostream>using namespace std;template<typename T, typename U>struct Pair{T first;U second;Pair():first(T()),second(U()){}Pair(const T&f, const U&s):first(f),second(s){}};template<typename T, typename U>void show(const Pair<T,U> p){cout << p.first << ',' << p.second << endl;}template<typename T, typename U>Pair<T,U> mkpair(T f, U s){return Pair<T,U>(f,s);}int main(){Pair<int ,double> p1;Pair<int, string> p2(100,"hello");show(p1);show(p2);show(mkpair('c', 5));show(Pair<char ,int>('c',5));return 0;}