Visual C ++变量声明

Question

In my MainApp.XAML.h file within the namespace brackets, I have:

int food;
food = 0;

When I compile the code I get a couple of errors saying:

Error C4430 missing type specifier - int assumed

and:

Error C2086 'int MonsterFights::food': redefinition

but when I google how to declare a variable, it shows the same way as I am doing.

Am I missing something?

--EDIT--

So if I need to put my variables in my .cpp file, where abouts in the .cpp file do I put them?

Currently I have it here:

MainPage::MainPage()
{
    InitializeComponent();
}
int food = 5;

Answer 1

There are two problems here:

1. The first is that you have a variable definition in the header file. That means the variable will be defined in every translation unit (roughly a source file with all included header files) where you include the header file.

   You can only have one single definition of each variable, and should only have declarations in the header file. Move the definition to a single source file, and have a declaration instead in the header file:

    extern int food; 

2. The second problem is that you can't have general statements in the global scope or in namespace scope, only declarations and definitions.

   You solve this by changing your definition (the one you have in a source file) to initialize the variable:

    int food = 0; 

   Note that this initialization is not really needed for global variables. The compiler will make sure that otherwise uninitialized global variables are suitable initialized to "zero", which for int variables means they will become 0 .