Deduce Two Independent Types

1#include <iostream>
2#include <string>
3 
4template <typename T, typename U>
5void showPair(T first, U second) {
6    std::cout << first << " " << second << "\n";
7}
8 
9int main() {
10    showPair(3, 4.5);
11    showPair('x', 10);
12    showPair(std::string("age"), 21);
13    showPair(2.5, 1.5);
14    showPair(1, 2);
15    return 0;
16}