c# - how to add strings together?

Question

public void button1_Click(object sender, EventArgs e)
{
    if (cushioncheckBox.Checked)
    {
        decimal totalamtforcushion = 0m;

        totalamtforcushion = 63m * cushionupDown.Value;
        string cu = totalamtforcushion.ToString("C");
        cushioncheckBox.Checked = false;
        cushionupDown.Value = 0;
    }

    if (cesarbeefcheckBox.Checked)
    {
        decimal totalamtforcesarbeef = 0m;
        totalamtforcesarbeef = 1.9m * cesarbeefupDown.Value;
        string cb = totalamtforcesarbeef.ToString("C"); 
        cesarbeefcheckBox.Checked = false;
        cesarbeefupDown.Value = 0;

    }
}

So i have these codes. How do i add the two strings, cb and cu together? I've tried doing

decimal totalprice;
totalprice = cu + cb;

but it says the name does not exist in the context. What should i do??

i'm using windows form btw

Answer 1

You have several issues here:

First of all, your string cu is declared inside the if scope. It will not exist outside that scope. If you need to use it outside the scope of the if, declare it outside.

Second, math operations cannot be applied to strings. Why are you casting your numeric values to string? Your code should be:

decimal totalamtforcushion = 0m;

if (cushioncheckBox.Checked)
{
    totalamtforcushion = 63m * cushionupDown.Value;
    //string cu = totalamtforcushion.ToString("C"); You don't need this
    cushioncheckBox.Checked = false;
    cushionupDown.Value = 0;
}

decimal totalamtforcesarbeef = 0m;
if (cesarbeefcheckBox.Checked)
{
    totalamtforcesarbeef = 1.9m * cesarbeefupDown.Value;
    //string cb = totalamtforcesarbeef.ToString("C");  you don't need this either
    cesarbeefcheckBox.Checked = false;
    cesarbeefupDown.Value = 0;

}

var totalprice = totalamtforcushion + totalamtforcesarbeef;