Careful with ternary operator

Issue

I was doing some Leetcode when I had Compile error regarding some arithmetic errors.

java.lang.ArithmeticException: / by zero

My code:

//long a = leftSum / (i + 1);
//long b = length-i==1 ? 0 : rightSum / (length-(i+1));
long diff = Math.abs(leftSum / (i + 1) - length-i==1 ? 0 : rightSum / (length-(i+1)));
if(diff<min){
    min = diff;
    res = i;
}

It worked just fine when I just did Math.abs (a-b) by inputting pre-calculated values inside Math.abs function. But when I tried saving some space by ridding a & b and putting all inside my diff variable, this error occurred.

Solution

You need a bracket to enclose the entire ternary operator as such:

- (length-i==1 ? 0 : rightSum / (length-(i+1)))