实验测试1《C++ Primer》第五版——第十四章 重载运算与类型转换

#include <iostream>
#include <map>
#include <utility>
#include <string>
#include <functional>

using namespace std;

class Int {
public:

Int(string i) : i(i) {
};

operator int() const {
return stoi(i);
}
private:
string i;
} ;

int add(int i, int j) {
return i + j;
}

int mod(int i, int j) {
return i % j;
};

struct divide {

int operator()(int denominator, int divisor) {
return denominator / divisor;
}
} ;

int main() {
map<string, function<int(int, int) > > binops = {
{"+", add},
{"-", std::minus<int>()},
{"/", divide()},
{"*", [](int i, int j) {
return i*j;
}},
{"%", mod}
};

cout << binops["+"](Int("10"), 5) << endl;
cout << binops["-"](10, Int("5")) << endl;
cout << binops["/"](Int("10"), 5) << endl;
cout << binops["*"](10, Int(
4000
"5")) << endl;
cout << binops["%"](Int("10"), 5) << endl;

return 0;
}