Main must return int error in C++ ?

 My program is the tempera trun to the Huashi  C:

 

  #include "iostream"

using namespace std;

class tempera
    {
     public:
      float cels;
      float change()
         {
           return (9*cels)/5+32;
         }
    };

void main()
  {
    tempera c;
    cout << "輸入攝氏溫度值："<<endl;
    cin >>c.cels;
    cout << "轉化為華氏溫度為:" << c.change() <<"度" <<endl;

.........................................................................................................................

I used the g++ to  build this program ,It always says "main must retrun int ".

 

bd@bd-desktop:~/Documents$ g++ -o tempera tempera.cpp
tempera.cpp:17: error: ‘::main’ must return ‘int’
bd@bd-desktop:~/Documents$

it should be "int main()" instead of "void main(void)" and then put a "return 0" at the end of the function.

這不是程式的問題，而是編譯器的問題

 

這是 C 語言標準的規定, 而 Dev C++ 嚴格的遵守這個規定.
DOS 版的 Turbo C 3 並不符合語言標準, 它沒錯誤並不表示它是對的.

 

（注意：main前面的一定要是int，既然main前面加了int那麼main函數裡必須有return語句）