/* Loan Calculator (15 points)

Write a C program that calculates the monthly payments for a mortgage loan. 
The program must perform the following steps: 1) read the loan amount, 
the number of years, and the annual interest rate (APR) from the keyboard; 
2) calculate the monthly interest rate from the annual interest 
rate (divide by twelve); 3) compute and print the monthly payment using 
the formula given below; 4) compute and print the total payment,
which is equal to the monthly payment times 12 times the number of years.

                             loanAmount * monthlyInterestRate
monthlyPayment =  ------------------------------------------------------
                                                 1
				   1 -   -----------------------------------------------
                         (1 + monthlyInterestRate)^ (numberOfYears * 12)

Where x^y means x raised to the y-th power.

*/


#include <stdio.h>
#include <stdlib.h>
#include <math.h>


int main()
{
	printf("Please enter loan amount: ");
	double loanAmount;
	scanf("%lf", &loanAmount);

	printf("Please enter number of years: ");
	int numberOfYears;
	scanf("%d", &numberOfYears);

	printf("Please enter APR: ");
	double APR;
	scanf("%lf", &APR);

	// calculate the monthly interest rate from the APR
	double monthlyInterestRate = (APR/100.0)/12.0;
		
	// compute the monthly payment
	double numerator = loanAmount*monthlyInterestRate;
	double denumerator = 1 - 1/( pow(1 +monthlyInterestRate, numberOfYears*12));
	double monthlyPayment = numerator / denumerator;

	double totalPayment = monthlyPayment * numberOfYears * 12;
	
	printf("\nThe monthly payment is: $%g\n\n", monthlyPayment);
	printf("The total payment is: $%g\n\n", totalPayment);

	system("pause");
}