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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 bool IsDecimal(string txt, string name)
{
if (Decimal.TryParse(txt, out _))
return true;
MessageBox.Show(name + " must be a decimal");
return false;
}
private bool IsInt32(string txt, string name)
{
if (Int32.TryParse(txt, out _))
return true;
MessageBox.Show(name + " must be an integer");
return false;
}
private bool IsWithinRange(string txt, string name, decimal min, decimal max)
{
if (Decimal.TryParse(txt, out decimal i))
if (i < min || i > max) {
MessageBox.Show(name + " must be in the range of "
+ min + " to " + max + "\n");
return false;
}
return true;
}
private bool IsValidData()
{
bool valid = true;
if(!IsDecimal(txtMonthlyInvestment.Text,
txtMonthlyInvestment.Name))
valid = false;
if(!IsWithinRange(txtMonthlyInvestment.Text,
txtMonthlyInvestment.Name, 0, 10000))
valid = false;
if(!IsDecimal(txtInterestRate.Text,
txtInterestRate.Name))
valid = false;
if(!IsWithinRange(txtInterestRate.Text,
txtInterestRate.Name, 0, 10000))
valid = false;
if(!IsInt32(txtYears.Text,
txtYears.Name))
valid = false;
if(!IsWithinRange(txtYears.Text,
txtYears.Name, 0, 10000))
valid = false;
return valid;
}
private void btnCalculate_Click(object sender, EventArgs e)
{
try {
if (!IsValidData())
return;
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();
/* throw new Exception("There was an unknown error"); */
}
/* catch (FormatException) {
MessageBox.Show("Invalid format: Try entering " +
"numbers between 1 and 9999", "Entry Error");
}
catch (OverflowException) {
MessageBox.Show("Overflow Error: Try entering"
+ "smaller numbers", "Entry Error");
} */
catch (Exception ex){
MessageBox.Show(ex.Message + "\n" +
ex.GetType().ToString() + "\n" +
ex.StackTrace, "Entry Error");
}
}
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 btnExit_Click(object sender, EventArgs e)
{
this.Close();
}
}
}
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