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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 frmFutureValue_Load(object sender, EventArgs e)
{
for (int i = 1; i <= 20; ++i)
cboYears.Items.Add(i);
cboYears.SelectedIndex = 2;
}
private void btnCalculate_Click(object sender, EventArgs e)
{
try {
if (IsValidData()) {
lstValues.Items.Clear();
decimal monthlyInvestment =
Convert.ToDecimal(txtMonthlyInvestment.Text);
decimal yearlyInterestRate =
Convert.ToDecimal(txtInterestRate.Text);
int years = (int)cboYears.SelectedItem;
int months = years * 12;
decimal monthlyInterestRate = yearlyInterestRate / 12 / 100;
for (int i = 1; i <= months; ++i)
if (i % 12 == 0) {
decimal futureValue = CalculateFutureValue(
monthlyInvestment, monthlyInterestRate, i);
lstValues.Items.Add("Year " + i/12 + ": "
+ futureValue.ToString("c"));
}
}
}
catch (Exception ex) {
MessageBox.Show(ex.Message + "\n\n" +
ex.GetType().ToString() + "\n" +
ex.StackTrace, "Exception");
}
}
public bool IsValidData()
{
bool success = true;
string errorMessage = "";
// Validate the Monthly Investment text box
errorMessage += IsDecimal(txtMonthlyInvestment.Text, txtMonthlyInvestment.Tag.ToString());
errorMessage += IsWithinRange(txtMonthlyInvestment.Text, txtMonthlyInvestment.Tag.ToString(), 1, 1000);
// Validate the Yearly Interest Rate text box
errorMessage += IsDecimal(txtInterestRate.Text, txtInterestRate.Tag.ToString());
errorMessage += IsWithinRange(txtInterestRate.Text, txtInterestRate.Tag.ToString(), 1, 20);
if (errorMessage != "") {
success = false;
MessageBox.Show(errorMessage, "Entry Error");
}
return success;
}
public static string IsPresent(string value, string name)
{
string msg = "";
if (value == "") {
msg += name + " is a required field.\n";
}
return msg;
}
public static string IsDecimal(string value, string name)
{
string msg = "";
if (!Decimal.TryParse(value, out _)) {
msg += name + " must be a valid decimal value.\n";
}
return msg;
}
public static string IsInt32(string value, string name)
{
string msg = "";
if (!Int32.TryParse(value, out _)) {
msg += name + " must be a valid integer value.\n";
}
return msg;
}
public static string IsWithinRange(string value, string name, decimal min, decimal max)
{
string msg = "";
if (Decimal.TryParse(value, out decimal number)) {
if (number < min || number > max) {
msg += name + " must be between " + min + " and " + max + ".\n";
}
}
return msg;
}
private decimal CalculateFutureValue(decimal monthlyInvestment,
decimal interestRateMonthly, int months)
{
decimal futureValue = 0m;
for (int i = 0; i < months; i++) {
futureValue = (futureValue + monthlyInvestment)
* (1 + interestRateMonthly);
}
return futureValue;
}
private void btnExit_Click(object sender, EventArgs e)
{
this.Close();
}
}
}
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