Question

Given an array A of 10 ints, initialize a local variable called sum and use a loop to find the sum of all numbers in the array A.

This was my answer that I submitted:

sum = 0;
while( A, < 10) {
   sum = sum += A;
}

I didn’t get any points on this question. What did I do wrong?

Answer 1

Your syntax and logic are incorrect in a number of ways. You need to create an index variable and use it to access the array’s elements, like so:

int i = 0;        // Create a separate integer to serve as your array indexer.
while(i < 10) {   // The indexer needs to be less than 10, not A itself.
   sum += A[i];   // either sum = sum + ... or sum += ..., but not both
   i++;           // You need to increment the index at the end of the loop.
}

The above example uses a while loop, since that’s the approach you took. A more appropriate construct would be a for loop, as in Bogdan’s answer.