variables never change~

Hi all, please search my code first:

#include <iostream>
#include <string>

class character
{
public:
void showX();
private:
int x;
};
void character::showX()
{
x=0;
cout << x << endl;
x++;
cout << x << endl;
}
void main()
{
character black;
black.showX();
black.showX();
}

finally, output shows:
0 1
0 1

it seems the x is initialized after being invoked a second time. it looks a bit like const not variable here, and it confused me much, what cause it be ???

>and it confused me much, what cause it be ???
Your question confuses me much, what is the problem? Every time showX is called, x is set to 0, printed, incremented, and then printed again. Aside from your ghastly use of undefined behavior, this is correct and predictable.

Code:

#include <iostream> 
#include <string> 

class character 
{ 
public: 
  void showX(); 
private: 
  int x; 
};

void character::showX() 
{ 
  x=0;
  /* Note that I had to change calls to cout,
  ** cin, and endl to include the namespace prefix
  ** since you don't have a using statement. I 
  ** also changed the first call to cout so that it
  ** ends with a space to create the exact output
  ** from your post.
  */
  std::cout << x << ' '; 
  x++; 
  std::cout << x << std::endl; 
}

// void main is wrong, main returns an int.
int main() 
{ 
  character black; 
  black.showX(); 
  black.showX(); 
}

--------
Output:

0 1
0 1

Could you be more specific as to what output you were expecting?

-Prelude

if you are expecting to get 0 and 1 the first time you call the showX() function and 1 and 2 the second time, then heres your problem. the x variable being private is only used by the showX function. the first time you run through it you set x to 0, cout that, then increment it and cout that. that gives you 0 1. now, if you run it again, it sets x to 0 via the first statement in the function, and couts that, then increments, then couts again. so, if you wanted it to show up 0 1 the first time then 1 2 the second time, make the int x public not private...that will work if you use the same class for your code in the main function. otherwise you should create a new version of showX that returns x. next time be clear on your question

soooooooooooooooooooooooooooory everyone, I found that it was some mistakes of my own, now it is solved, Cheers~