对重载函数调用不明确

花开自有丶花落

对重载函数调用不明确，搞不懂
和书上一样却编译不了

1. #include <iostream>
   
2. #include <cstdlib>
   
3. 
   
4. using namespace std;
   
5. template <typename T>
   
6. void swap(T & a, T & b);
   
7. int main()
   
8. {
   
9.     int i=10;
   
10.     int j=20;
    
11.     cout<<"i,j = "<<i<<", "<<j<<endl;
    
12.     cout<<"using compiler generated int swaper:\n";
    
13.     swap(i,j);
    
14.     cout<<"i,j = "<<i<<", "<<j<<endl;
    
15.     double x = 24.5;
    
16.     double y = 81.7;
    
17.     cout<<"x,y = "<<x<<", "<<y<<endl;
    
18.     cout<<"using compiler generated int swaper:\n";
    
19.     swap(x,y);
    
20.     cout<<"x,y = "<<x<<", "<<y<<endl;
    
21.     system("pause");
    
22.     return 0;
    
23. }
    
24. template <typename T>
    
25. void swap(T & a, T & b)
    
26. {
    
27.      T temp;
    
28.      temp = a;
    
29.      a = b;
    
30.      b = temp;
    
31. }
    

复制代码

littlestar

因为用了using namespace std; 内置的swap是在std空间的 所以会有两个swap函数 要么改下函数名 要么去掉using namespace std， 在cout endl前加std::就ok

1. #include <iostream>
   
2. #include <windows.h>
   
3. 
   
4. 
   
5. template <typename T>
   
6. void swap(T &a, T &b) {
   
7.      T temp;
   
8.      temp = a;
   
9.      a = b;
   
10.      b = temp;
    
11. }
    
12. int main()
    
13. {
    
14.    
    
15.     int i=10;
    
16.     int j=20;
    
17.     std::cout<<"i,j = "<<i<<", "<<j<<std::endl;
    
18.     std::cout<<"using compiler generated int swaper:\n";
    
19.     swap(i,j);
    
20.     std::cout<<"i,j = "<<i<<", "<<j<<std::endl;
    
21.     double x = 24.5;
    
22.     double y = 81.7;
    
23.     std::cout<<"x,y = "<<x<<", "<<y<<std::endl;
    
24.     std::cout<<"using compiler generated int swaper:\n";
    
25.     swap(x,y);
    
26.     std::cout<<"x,y = "<<x<<", "<<y<<std::endl;
    
27.     system("pause");
    
28.    
    
29.     return 0;
    
30. }
    

复制代码

花开自有丶花落

swap是系统里一个函数，在名称空间std中，重载了swap函数，改掉函数名成功编译