Problems with array

albert albert

Hi Everyone,

I have this:

[code]
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace VendingMachineApp
{
public partial class Form1 : Form
{
VendorMachine vendorMachine;
public String[] snacks = { "Cookie", "Bubble gum", "Prefzels", "Soda" };
string line = "has been dispended";
int choose;
int i;
public Form1()
{
InitializeComponent();
}

private void button1_Click(object sender, EventArgs e)
{
string[] snacks = new string[4];
snacks[0] = "Cookie";
snacks[1] = "gum";
snacks[2] = "Prefzels";
snacks[3] = "soda";

switch (snacks[choose])
{
case snacks[0] :txtOutput.Text = snacks[0] + line;
break;
case snacks[1]: txtOutput.Text = snacks[1] + line;
break;
case snacks[2]: txtOutput.Text = snacks[2] + line;
break;
case snacks[3]: txtOutput.Text = snacks[3] + line;
break;
default:
break;
}//end swicth

}
}
}

[/code]

but what has to be for the case? case snacks[1] - then I get an error: "A constant value is expected".

I just want if user put an 1 in a textbox that u get as outcome: "gum" and for 2 - outcome: "prefzels".

THX

4 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes15y ago
Accepted answer
That's because you haven't set the 'choose' variable which therefore still has its default value of 0.

You need to insert this line before you enter the switch statement:

int.TryParse(txtChoose.Text, out choose);

If an invalid number is entered in the textbox, then 0 will be used instead.

To make sure that choose is within bounds, you could also add these lines:

if (choose < 0)
choose = 0;
else if (choose > 3)
choose = 3;
albert albert15y ago
THX. Yes I will do the exception handling now
albert albert15y ago
Hi Vulpes,

I had that , but then the problem is that only the first line: cookie is shown.For example if u put a 2 in the textbox and press the button u still get cookie back and not Prefzels:

switch (choose)
{
case 0 :txtOutput.Text = snacks[0] + " " + line;
break;
case 1: txtOutput.Text = snacks[1] + " " + line;
break;
case 2: txtOutput.Text = snacks[2] + " "+ line;
break;
case 3: txtOutput.Text = snacks[3] + " " +line;
break;
default:
break;
}//end swicth

also for this: txtOutput.Text = snacks[choose];
Vulpes15y ago
The switch statement needs to be coded like this as you can only use constants for the 'case' expressions:

switch (choose)
{
case 0 : txtOutput.Text = snacks[0] + line;
break;
case 1 : txtOutput.Text = snacks[1] + line;
break;
case 2 : txtOutput.Text = snacks[2] + line;
break;
case 3 : txtOutput.Text = snacks[3] + line;
break;
default:
break;
}//end swicth

Alternatively, you could simply do:

txtOutput.Text = snacks[choose] + line;