Question

I’ve started learning C++. Here’s my simple problem. I have a code:

int main() {
  int number;
  cout << "Input number: ";
  cin >> number;
  cout << "here is hex = 0x" 
       << hex << number << endl;
}

I’m using Visual C++. I think the point of this program is easy, user enters some number and program converts it to hex value. But when I enter some number and hit enter, console window just closes. How to display hex inside console window?

Answer 1

Try to include cstdlib and add system("PAUSE"); to your main:

#include <cstdlib>

int main()
{
  int number;
  cout << "Input number: ";
  cin >> number;
  cout << "here is hex = 0x" 
       << hex << number << endl;
  system("PAUSE");
  return 0;
}

That’s it, happy programming 😉

Instead of pausing you could also use getch() from conio.h. This waits for a key, so the console window wont close until you hit any key…

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From the comments, to get PI in C++ just add the following to your header:

#define _USE_MATH_DEFINES
#include <cmath>

and you’ll have access to the variable M_PI 🙂