C++头文件报错

kingfighters

学习C++的时候，想看一下操作符重载，找了网上的一段代码：

1. //complex.h
   
2. #include <iostream>
   
3. 
   
4. using namespace std;
   
5. class Complex//声明一个复数类
   
6. {
   
7.    public:
   
8.    Complex(Complex &a);//拷贝构造函数
   
9.    Complex(double r=0,double i=0);
   
10.    void display();//输出复数的值
    
11.    void set(Complex &a);
    
12.    Complex plus(Complex a);//复数的加法
    
13.    Complex minus(Complex a); //复数的减法
    
14.    Complex plus(double r); //复数与实数相加
    
15.    Complex minus(double r); //复数与实数相减
    
16.    private:
    
17.    double real;//复数实部
    
18.    double img;//复数虚部
    
19. };
    
20. Complex::Complex(Complex &a)
    
21. {
    
22.    real=a.real;
    
23.    img=a.img;
    
24. }
    
25. Complex::Complex(double r,double i)
    
26. {
    
27.    real=r;
    
28.    img=i;
    
29. }
    
30. void Complex::display()
    
31. {
    
32.    cout <<real <<(img>=0?"+":"") <<img <<"i";//适合显示1-3i等虚部为负值的复数
    
33. }
    
34. void Complex::set(Complex &a)
    
35. {
    
36.    real=a.real;
    
37.    img=a.img;
    
38. }
    
39. Complex Complex::plus(Complex a)
    
40. {
    
41.    Complex temp(a.real+real,a.img+img);
    
42.    return temp;
    
43. }
    
44. Complex Complex::minus(Complex a)
    
45. {
    
46.    Complex temp(real-a.real,img-a.img);
    
47.    return temp;
    
48. }
    
49. Complex Complex::plus(double r)
    
50. {
    
51.    Complex temp(real+r,img);
    
52.    return temp;
    
53. }
    
54. Complex Complex::minus(double r)
    
55. {
    
56.    Complex temp(real-r,img);
    
57.    return temp;
    
58. }
    

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然后是cpp文件：

1. #include "complex.h"
   
2. #include <iostream>
   
3. using namespace std;
   
4. int main()
   
5. {
   
6.    Complex a(3,2),b(5,4),temp;
   
7.    temp.set(a.plus(b));//temp=a+b
   
8.    temp.display();
   
9.    cout <<endl;
   
10.    temp.set(a.minus(b));//temp=a-b
    
11.    temp.display();
    
12.    cout <<endl;
    
13.    return 0;
    
14. }
    

复制代码

怎么都在ubuntu下的GCC编译不过去，主要是如下错误：
g++ -Wall -c "complex.cpp" (in directory: /home/oliver/course/c++ for c programmer/code)
complex.cpp: In function ‘int main()’:
complex.cpp:7:22: error: no matching function for call to ‘Complex::set(Complex)’
complex.cpp:7:22: note: candidate is:
In file included from complex.cpp:1:0:
complex.h:33:6: note: void Complex::set(Complex&)
complex.h:33:6: note:   no known conversion for argument 1 from ‘Complex’ to ‘Complex&’
complex.cpp:10:23: error: no matching function for call to ‘Complex::set(Complex)’
complex.cpp:10:23: note: candidate is:
In file included from complex.cpp:1:0:
complex.h:33:6: note: void Complex::set(Complex&)
complex.h:33:6: note:   no known conversion for argument 1 from ‘Complex’ to ‘Complex&’
Compilation failed.

尝试编译.h文件，得到的报错如下：
gcc -Wall -c "complex.h" (in directory: /home/oliver/course/c++ for c programmer/code)
complex.h:1:20: fatal error: iostream: No such file or directory
compilation terminated.
Compilation failed.


我把.h文件改成.cpp文件，能够编译通过。实在搞不懂什么情况了。求教

myworkstation

回复 1# kingfighters

把函数原型void Complex::set(Complex &a)修改为void Complex::set(const Complex &a)，
你调用的代码：temp.set(a.plus(b));//temp=a+b，你的注释也说明了参数是个临时对象，而临时对象是无法转换为引用的，只能常(const)引用。
至于你编译头文件有总是是因为你编译用的是gcc而不是g++，这两个命令默认的编译环境不一样。