How to Calculate Sale Percentage on C# Form

Question

I haven't used C# in many years an need basically a 1 liner. I have created a bus ticket booking form of which I have a combobox for destinations and radio button for Class Types. The Middle class price from JHB to PTA is R85.50, Economy price is 30% off the middle class and Luxury 50% extra from the Middle Class.

So when the Total button is clicked then

private void btnTotal_Click(object sender, EventArgs e)
    {
        if ((CboxDestination.Text == "JHB To PTA")&&(rdbEconomy.Checked))
        {

            lblTotal = ???;

Ive tried my calculations but i get different errors, 1 being that i'm trying to use a double on a string. I had already tried declaring JHbToPTA as a double.

using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Railway_Booking
{
    public partial class Form1 : Form
    {
        Double JHBToPTA = 85.50;

Please anyone help fill in the correct calculation, i'm really bad in percentages but the answer should = to 59.85

Answer 1

Seems like my issue was not really about the Math. I worked it out like so:`

public partial class Form1 : Form
{
        decimal ToPTA = 85.50m;
        decimal discount = (0.7m/ 100) *100;

` so added an m to my decimals

And then my label display converted to string

 lblTotal.Text = Convert.ToString(ToPTA *  discount);

Thanks again

Answer 2

it's okay, I'm also weak in maths, but there's a simple formula for percentage.

if you want to get a percentage, the formula is: (marks you got / total marks) * 100

if you have Got percentage, but don't know how much marks you have got(but you do know the total marks) then the formula will be: My Marks = (Total marks * percentage marks) / 100

in your case, I can see that you have declared JHBToPTA as a "double" type, but since it's currency, you should have chosen the "decimal" type. it'll be more convenient.

since the economy price is 30% of the middle class, then to get the price the formula will be,

(30 * 85.50) / 100 = 25.65

so, if you give a discount of 30 percent, then you just have to subtract 25.65 from the middle-class price ie 85.50 - 25.65 = 59.85

using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Railway_Booking
{
    public partial class Form1 : Form
    {
        decimal JHBToPTA = 85.50;
        decimal discount = (30 * JHBToPTA) / 100
        decimal final_price = JHBToPTA - discount  //i.e. 59.85