c++ 引用类型以及函数指针

 1 #include "stdafx.h"
 2 #include <iostream>
 3 #include <string>
 4 #include <fstream>
 5 #include <cmath>
 6 using namespace std;
 7 typedef int& ex(int &, int &);
 8 int& exchange(int &, int &);
 9 void acb(ex,int &,int &);
10 
11 int main() {
12     int a = 123,b = 999;
13     acb(exchange, a, b);
14     cout << a << "   " << b << endl;
15     system("pause");
16 }
17 
18 void acb(ex e,int &a,int &b) {
19     cout << e << endl;
20     ex *exx = e;
21     exx(a, b) = 998;
22     //cout << exx(a, b) << endl;
23 }
24 
25 int& exchange(int &a, int &b) {
26     int temp;
27     temp = a;
28     a = b;
29     b = temp;
30     double c = 1.3;
31     return b;
32 }