Dividing by zero warning

Question

I have a problem with dividing by zero exception in my program. I tried several tricks, but none of them worked. What should I change in my code to avoid dividing by zero?

I know that I have to add some additional statements in "IF" part of my code, but I still have no idea what exactly should I do.

for (counter = 0; counter < numbers.Length; counter++)
{
    string input = Console.ReadLine();

    if(string.IsNullOrEmpty(input))
    {
        break;
    }
    else
    {
        int.TryParse (input, out numbers[counter]);
    }
}

for (int i = 0; i < numbers.Length; i++) {
    sum += numbers [i];

    if (numbers [i] % 3 == 0 && numbers [i] % 9 != 0) {
        div3not9++;
    }

    if (numbers [i] >= 11 && numbers [i] <= 131 && (numbers [i] * numbers [i] % 7 == 0) && (numbers [i] * numbers [i] % 3 != 0)) {
        range11to131sqdiv7not3++;
        SUMrange11to131sqdiv7not3 += numbers [i];

        if (range11to131sqdiv7not3 > 0) {
            mean = SUMrange11to131sqdiv7not3 / range11to131sqdiv7not3;
        }
            else
                mean = 0;
        }

    }

for (int y = 0; y < numbers.Length; y++) {
    if (numbers [y] > 0)
        min = numbers [y];
}
for (int r = 0; r < numbers.Length; r++) {
    if (numbers [r] < min && numbers [r] > 0)
        min = numbers [r];

    if (numbers [r] % min == 0) {
        divmin++; // DIVISION BY ZERO EXCEPTION
    }

    if (sum % numbers [r] == 0) {
        divisorsofsum++;  // DIVISION BY ZERO EXCEPTION
    }
}

Answer 1

The division by zero is caused by your use of the % operator. This operator returns the remainder of a division and so will fail if the second operand is zero.

So, if

numbers[r] % min

leads to a zero divide error, then min is zero. You'll need to treat that case specially. And similarly for the other use of the % operator.

Answer 2

change the last for statement to:

for (int r = 0; r < numbers.Length; r++) {
    if (numbers [r] < min && numbers [r] > 0)
        min = numbers [r];

    if (min == 0)
    {
      // What to do when min is 0 is up to you
    }
    else
    {
       if (numbers [r] % min == 0) {
           divmin++;
       }

       if (sum % numbers [r] == 0) {
           divisorsofsum++;
       }
    }
}

because min mustn't be 0, because when doing x%min you are actually dividing by min and check for the remaining