MCC - CIS162AD CS5ex Decisions - Programming Example

CS5ex is an example that is demonstrated in the structured class after the lecture on Decisions and Conditions. The source code listed below is then reviewed in detail. Students should referred to this code when completing their CS5 assignment. Students are NOT required to create and submit this project, but students may download and expand the self-extracting CS5ex archive into their own workspace if they like.

CS5ex Sample Form:

CS5exForm.cs Source Code:

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

//CS5ex by Your Name - CIS162AD
/*    
    This project uses if statements to validate the 
    quantity and price entered.  If valid, they are used
    to calculate the extended price, sales tax, shipping, 
    and total due.  If the quantity is greater than 25, a
    discount of 2% is given. The extended price is accumulated
    to determine the total of all of the orders entered.
    The number of orders entered are also counted, and 
    the accumulated extended price and number of orders entered
    are used to calculate the average order amount.
    Constants are used to store the sales tax and shipping rates.
*/

namespace CS5ex
{
    public partial class CS5exForm : Form
    {
        public CS5exForm()
        {
            InitializeComponent();
        }

        //Declare class-level variables and constants
        //Class variables are initialized to zero when declared
        int cintOrderCount;
        decimal cdecGrandTotal;

        const decimal cdecTAX_RATE = 0.08M;
        const decimal cdecDISCOUNT_RATE = .98M;  //98% of the price is a 2% discount
        const decimal cdecGROUND_SHIPPING_RATE = 5.00M;
        const decimal cdecTHREE_DAY_SHIPPING_RATE = 7.00M;
        const decimal cdecNEXT_DAY_SHIPPING_RATE = 10.00M;

        private void btnCalculate_Click(object sender, EventArgs e)
        {
            // declare method variables
            int intQuantity;
            decimal decPrice;
            decimal decExtendedPrice;
            decimal decSalesTax;
            decimal decShipping;
            decimal decTotalDue;
            decimal decAverageOrder;
 

            //Input:
            //Use nested try-catch blocks to get the input values
           try
           {
                //Use a try-catch block to catch non-numeric values
                intQuantity = int.Parse(txtQuantity.Text);
                decPrice = decimal.Parse (txtPrice.Text);
                
                //Process:
                //We now have a numeric quantity and price.
                //Check if values are within the range
                if (intQuantity >= 1 && intQuantity <= 50)
                    if (decPrice >= 5.00M && decPrice <= 15.00M)
                    {
                        //Values are valid - Continue processing 

                        //Determine if discount should be applied
                        if (intQuantity > 25)
                            decExtendedPrice = intQuantity * (decPrice * cdecDISCOUNT_RATE);
                        else
                            decExtendedPrice = intQuantity * decPrice;

                        //Calculate sales tax if taxable
                        if (chkSalesTax.Checked == true)
                            decSalesTax = decExtendedPrice * cdecTAX_RATE;
                        else
                            decSalesTax = 0M;

                        //Determine shipping amount
                        if (radNextDay.Checked == true)
                            decShipping = cdecNEXT_DAY_SHIPPING_RATE;
                        else if (radThreeDay.Checked == true)
                            decShipping = cdecTHREE_DAY_SHIPPING_RATE;
                        else
                            decShipping = cdecGROUND_SHIPPING_RATE;

                        //Sum to get the total due
                        decTotalDue = decExtendedPrice + decSalesTax + decShipping;

                        //Accumulate summary totals
                        cdecGrandTotal += decTotalDue;
                        cintOrderCount += 1;
                        decAverageOrder = cdecGrandTotal / cintOrderCount;

                        //Output:
                        //We now have all of the values to display
                        lblExtendedPrice.Text = decExtendedPrice.ToString("C");  //Currency
                        lblSalesTax.Text = decSalesTax.ToString("C");
                        lblShipping.Text = decShipping.ToString("C");
                        lblTotalDue.Text = decTotalDue.ToString("C");

                        lblGrandTotal.Text = cdecGrandTotal.ToString("C");
                        lblNumberOfOrders.Text = cintOrderCount.ToString("N0"); //Number
                        lblAverageOrder.Text = decAverageOrder.ToString("C");

                        txtQuantity.Focus();    //get ready for next input
                    }
                    else
                    {
                        //Handle invalid price
                        MessageBox.Show("Price must be between $5.00 and $15.00. ", 
                            "Data Entry Error", MessageBoxButtons.OK, 
                            MessageBoxIcon.Exclamation);
                        txtPrice.SelectAll();
                        txtPrice.Focus();
                    }//endif
                else
                {
                    //Handle invalid quantity
                    MessageBox.Show("Quantity must be between 1 and 50. ",
                        "Data Entry Error", MessageBoxButtons.OK, 
                        MessageBoxIcon.Exclamation);
                    txtQuantity.SelectAll();
                    txtQuantity.Focus();
                }//endif
            }
            //Handle exceptions for quantity and price
            catch (FormatException err)
            {
                MessageBox.Show("Quantity or Price not numeric. Enter again. "
                    + err.Message, "Data Entry Error", MessageBoxButtons.OK, 
                    MessageBoxIcon.Exclamation);
                txtQuantity.SelectAll();
                txtQuantity.Focus();
            }
            //Handle any other exceptions.   
            catch(Exception err)
            {
                MessageBox.Show("Unexpected Error: " + err.Message);
            }
        }//end of btnCalculate


        private void btnClearForm_Click(object sender, EventArgs e)
        {
            //Use Clear or null string "" for TextBoxes, but
            //only use null string "" for Labels

            txtQuantity.Clear();        //Clear
            txtPrice.Clear();

            lblExtendedPrice.Text = "";   //null string
            lblSalesTax.Text = "";
            lblShipping.Text = "";
            lblTotalDue.Text = "";
            lblGrandTotal.Text = "";
            lblNumberOfOrders.Text = "";
            lblAverageOrder.Text = "";

            radGround.Checked = true;
            chkSalesTax.Checked = false;

            cdecGrandTotal = 0;        //Reset Accumulators
            cintOrderCount = 0;

            txtQuantity.Focus();

        }//end of btnClearForm


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


    }//end of class
}//end of namespace