using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FutureValue
{
	public partial class frmFutureValue : Form
	{
		public frmFutureValue()
		{
			InitializeComponent();
		}

		private void btnCalculate_Click(object sender, EventArgs e)
		{
			decimal monthlyInvestment = Convert.ToDecimal(txtMonthlyInvestment.Text);
			decimal yearlyInterestRate = Convert.ToDecimal(txtInterestRate.Text);
			int years = Convert.ToInt32(txtYears.Text);

			int months = years * 12;
			decimal monthlyInterestRate = yearlyInterestRate / 12 / 100;

			decimal futureValue = this.CalculateFutureValue(
				monthlyInvestment, monthlyInterestRate, months);
			txtFutureValue.Text = futureValue.ToString("c");
			txtMonthlyInvestment.Focus();
		}

		private decimal CalculateFutureValue(decimal monthlyInvestment,
			decimal monthlyInterestRate, int months)
		{
			decimal futureValue = 0m;
			for (int i = 0; i < months; i++)
				futureValue = (futureValue + monthlyInvestment)
					* (1 + monthlyInterestRate);
			return futureValue;
		}

		private void ClearFutureValue(object sender, EventArgs e)
		{
			txtFutureValue.Text = "";
		}

		private void frmFutureValue_DoubleClick(object sender, EventArgs e)
		{
			txtMonthlyInvestment.Text = "";
			txtInterestRate.Text = "";
			txtYears.Text = "";
			txtFutureValue.Text = "";
			txtMonthlyInvestment.Focus();
		}

		private void txtInterestRate_DoubleClick(object sender, EventArgs e)
		{
			txtInterestRate.Text = "12";
		}
		private void txtYears_DoubleClick(object sender, EventArgs e)
		{
			if (txtYears.Text == "")
				txtYears.Text = "1";
			else
				txtYears.Text = (int.Parse(txtYears.Text)
					+ 1).ToString();
		}

		private void btnExit_Click(object sender, EventArgs e)
		{
			this.Close();
		}
	}
}