How can I count how often a specific char appears before other specific char appears for the first time?

Question

I have a string like asdafahxlkax.

How can I count that a appears 3 times before the first x appears?

Answer 1

String str = "asdafahxlkax"; 
char[] chars = str.ToCharArray();

int counter = 0;
for (int i = 0; i < chars.Length; i++)
{
    if(chars[i] == 'a')
    {
        counter++;
    }
    else if(chars[i] == 'x')
    {
        if(counter == 3)
        {
            // success
        }
        else
        {
            // fail
        }
    }
}

You need to define if you want this to fail when x is contained 0 times. But in general this is a simple approach.