Thread: I need help with my code

Hello guys I am a beginner in programming and I have this assignment to count mortgage. The variables given are
Principle: 150k
Monthly Payment: 6648.09
How long: 3 years or 36 months

Code:

#include "stdafx.h"
#include <stdio.h>




int main()
{
    /* declare variable */


    double principle = 150000.00;
    double interest = 0.06;
    double payMonthly = 6648.09;
    double balance;
    int years = 3;
    int months = 1;




    /* finding multipler */
    double multiplier;
    multiplier = interest / 12;


    /* calculating balance per month */
    double monthlyInterest;
    double monthlyPayment;
    double newBalance;


    monthlyInterest = principle * multiplier;
    monthlyPayment = payMonthly - monthlyInterest;
    newBalance = principle - monthlyPayment;
    do
    {
        monthlyInterest = principle * multiplier;
        monthlyPayment = payMonthly - monthlyInterest;
        newBalance = principle - monthlyPayment;


        printf("Mortgage for the %d month. \n", months);
        months = months + 1;
        printf("Principle: %.2lf Interest: %.2lf Deduction: %.2lf \n", principle, monthlyInterest, monthlyPayment);
        printf("Balance: %.2lf \n", newBalance);
    } while (months < 36);


    return 0;
}

When I run it, it does the loop but the numbers not updated. How do I go about fixing this?? thank you.