Lab4 - Loan

void setup() {
  size(450, 270);
  background(0);
  float loanAmount = 5000;
  float interestPercent = 12;
  int loanTerm = 12;

  loan(loanAmount, interestPercent, loanTerm);
}

void loan(float loanAmount, float interestPercent, int loanTerm) {
  float interestRate = interestPercent/100;
  float effectiveInterest = interestRate/12;
  float monthlyPayment = loanAmount*(effectiveInterest/(1-pow(1+effectiveInterest, -loanTerm)));
  head(30, 20);

  float interest = 0;
  float totalInterest = 0;
  float principal = 0;
  float balance = loanAmount;
  int term = 1;
  while (term <= loanTerm) {
    interest = balance * effectiveInterest;
    principal = monthlyPayment-interest;
    totalInterest += interest;
    balance -= principal;
    if (balance <= 0) {
      balance = 0;
    }
    showValue(term, balance, principal, interest, totalInterest, 30, 20*(1+term));
    term++;
  }
}

void showValue(int term, float balance, float principal, float interest, float totalInterest, int x, int y) {
  int space = 80;
  fill(#FFFF00);
  text(term, x, y);
  text("$"+nf(principal, 1, 2), x+space, y);
  text("$"+nf(interest, 1, 2), x+space*2, y);
  text("$"+nf(balance, 1, 2), x+space*3, y);  text("$"+nf(totalInterest, 1, 2), x+space*4, y);
}

void head(int x, int y) {
  int space = 80;
  fill(#FF0000);
  text("Payment No.", x, y);
  text("Principal", x+space, y);
  text("Interest", x+space*2, y);
  text("Balance", x+space*3, y);  text("Total Interest", x+space*4, y);
}