接受int形参(double,,等等)返回int（...）;并且一个vector对象保存指向这些函数的指针;进行加减乘除;输出结果

#include <bits/stdc++.h>using namespace std;int f1(int a,int b){    return a+b;}int f2(int a,int b){    return a-b;}int f3(int a,int b){    return a*b;}int f4(int a,int b){    return a/b;}int main(){    vector<int(*)(int,int)> v;    v.push_back(f1);    v.push_back(f2);    v.push_back(f3);    v.push_back(f4);    cout << v[0](1,2) << endl;    cout <<v[1](1,2) << endl;    cout << v[2](1,2) << endl;    cout << v[3](2,1) << endl;    return 0;}