Arrays, Specifically Char Arrays

Question

private void Benter_Click(object sender, EventArgs e)
        {
            string mainString = INmain.Text;
            string chars = "+-x/";
            char [] charArray = chars.ToCharArray();
            INmain.Text = charArray.ToString();
            for (int i = 0; i >= 4; i++)
            {
                int tempInt = mainString.IndexOfAny(charArray);
                INmain.Text = tempInt.ToString();
            }
        }

Benter is my 'Enter' button.
INmain is my inputbox.

The problem is the output is always System.Char[], regardless of the input.
I can do the same thing without a Char Array -and it works, but it increases my code threefold.
If you can't tell I am horrible with arrays.

Answer 1

Sorry for the double post, but I also tried this (it still gives me the same problem):

private void Benter_Click(object sender, EventArgs e)
        {
            string mainString = INmain.Text;
         //   string chars = "+-x/";
            char [] charArray = {'+','-','x','/'};
          //  INmain.Text = charArray.ToString();
            for (int i = 0; i >= 4; i++)
            {
                  int tempInt = mainString.IndexOfAny(charArray);
                  INmain.Text = INmain.Text + tempInt.ToString();
            }
             
        }

Answer 2

You need to use the i in the for loop.  Try changing (charArray) to (charArray[i]).

EDIT:
Actually...what are you trying to accomplish.  Also, you might want to change i >= 4 to i < 4 since there are only 4 items in your array that I'm assuming you want to loop through?  

Answer 3

I was making a calculator.
The whole point was to make it 'fancy.'
Where you could input almost any equation and it solves it for you.
Such as the quadratic equation:
x=(-b +/- √(b^2 -4a*c)) / (2*a)

Well lets use a simpler example
(-9)+87*52
It would get the index of each operator, save it to an int, and save the value between
each index as a number. Then get the value of the index of the operator and save it to a
char. If I was to do it without using a char array I would have to do .LastIndexOf, for each
possible operation. Then check to see the placement of the index. Whereas with the Char
Array I can use the .LastIndexAny witch would automatically give me the last index of the
last operator. Then I can set the start value of the .LastIndexOfAny (which would be in a loop)
to the value of the last found operator+1. And that could be repeated for all of the operators.
So:
(   = char
-   = char
9   = int
)   = char
+  = char
87 = int
*   = char
52 = int

Then it would do the operation between each number.
P.S. It would multiply the 9 by -1.

Answer 4

If you want to have the indices of all the operators, you need to tell IndexOfAny to not search from the start every time.

List<int> getOperators(string equation) 
{
    char[] operators = { '+', '-', '*', '/' };
    List<int> indices = new List<int>();
    int i = equation.IndexOfAny(operators);
    while(i != -1)
    {
        indices.Add(i);
        i = equation.IndexOfAny(operators, i);
    }
    return indices;
}