Parse string with arithmetic operation

Question

I have a string of the following type:

"23 + 323 =" or "243 - 3 ="

So the format is: number + operator + number = equal.

And I also have an int which is the answer to that question.

How can I parse the string and check if the answer is correct?

Thank You, Miguel

Answer 1

Maybe using regular expressions you can do something like...

String sExpression = "23 + 323 =";
int nResult = 0;
Match oMatch = Regex.Match(@"(\d+)\s*([+-*/])\s*(\d+)(\s*=)?")
if(oMatch.Success)
{
    int a = Convert.ToInt32(oMatch.Groups[1].Value);
    int b = Convert.ToInt32(oMatch.Groups[3].Value);
    switch(oMatch.Groups[2].Value)
    {
        case '+';
            nResult = a + b;
            break;
        case '-';
            nResult = a - b;
            break;
        case '*';
            nResult = a * b;
            break;
        case '/';
            nResult = a / b;
            break;
    }
}

and extend to your need.. (floats, other operators, validations, etc)