My awesome C++ triangle

//Homework 2, question 5

#include <iostream>
using namespace std;

int main(void)
{
 int n;
 int r, c;

 cout << "Enter a number: ";
 cin >> n;
 
 n = 2 * n + 2;
 
 for (r = 1; r <=n; r++, cout << endl)
     for (c = 1; c <=n; c++)
         cout << (r==1 || r==n || c==1 || c==n
              || r >= c || (r+c < n+1) ? ' ' : '*');

 return 0;  
}

It's not even undefined behavior!
5.1.2.2.3 Program termination
1 If the return type of the main function is a type compatible with int, a return from the initial call to the main function is equivalent to calling the exit function with the value returned by the main function as its argument;10) reaching the } that terminates the main function returns a value of 0. If the return type is not compatible with int, the termination status returned to the host environment is unspecified.
Look at this part:
reaching the } that terminates the main function returns a value of 0.
Also the line break in the string literal is caused by word wrapping on the text board, not a newline.