Program runs, but I would like it to exit with a negative number input

My first time posting. This program is/was a homework problem. It works as required, but I would like to eliminate negative numbers and have it exit with the input of a negative rather than zero. All mods i have made just screwed it up and I know it's simple. What areas need to be changed to get this ?

Code:

#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;

class Numbers
{
private:
    int number;   

public:
   
     Numbers(int a)
       {number=a;}
     void print();
};


void Numbers::print()
{
	int n;
	string lessthan20[20]={"zero","one","two","three","four","five","six","seven",
                   "eight","nine","ten","eleven","twelve","thirteen",
                     "fourteen","fifteen","sixteen","seventeen",
                     "eighteen","nineteen"};

	string tens[10]={"zero","ten","twenty","thirty","forty","fifty","sixty",
                 "seventy", "eighty", "ninety"};
	if(number<0)
	 cout<<"negative ";
	 number=abs(number);
	 n=number/1000;
    if(n>0)
     cout<<" "<<lessthan20[n]<<" thousand ";
	 number%=1000;

	 n=number/100;
	if(n>0)
     cout<< lessthan20[n]<<" hundred ";
	 number%=100;
	if(number>=20)
    {
        n=number/10;           
        if(n>0)        
           cout<<tens[n]<<" ";
    }
         else if(number>=10)
    { 
         cout<< lessthan20[number]<<" ";
        return;
    }
	 number%=10;
	if(number>0)
     cout<<lessthan20[number];
     cout<<" ";

}

int main()
{
    int n;
    cout<<" This program will take an input of up to four(4) numerals\n";
    cout<<" and change them to a written number.\n";
    cout<<" Enter up to a four-digit number(0 to exit): ";
    cin>>n;    
    while(n!=0)
   {
        Numbers number(n);
        number.print();

       cout<<"\nEnter a number(0 to exit): ";
       cin>>n;  
   }
system("pause");
return 0;
}

Originally Posted by msanak

I would like to eliminate negative numbers and have it exit with the input of a negative rather than zero.

Just change the loop condition from (n!=0) to (n >= 0).

Consistent and good indentation would help. I suspect you have lots of bugs where missing curly braces should be.

I knew it was a simple fix. When looking over my code after the response, I just gave a whack to the forhead and thought'stupid! It was staring at you- take out the ! when you change the loop, don't leave it there" Thanks for pointing out what i was missing.