How to check if all the values of an array are equal to 0?

Question

The context of the program is a game involving pegs and discs. The user inputs the amount of pegs (max of 20) and the amount of discs on each peg (max of 10). Two players go

Answer 1

try memcmp instead of having separate function with for loop:

int zeros[sizeof(yourArray)];
if(memcmp(yourArray,zeros,sizeof(yourArray))==0)
//do things
else
//do things

Answer 2

bool checkPegs(int array[], int size)
{
  for (int i = 0; i < size; i++)
  {
      if(array[i] != 0)
      {
        return false;
      }
  }
  return true;
}

Answer 3

there are two errors here

bool checkPegs(int array[], int size)
{
  int checker(0);
  for (int i = 0; i < size; i++)
  {
      if(array[i] = 0) // the first one use '==' instead of '='
      {
        return true; // the second one, you are testing the first element only
      }
      else
      {
        return false;
      }
  }
}

here how it should be

bool checkPegs(int array[], int size)
{

  for (int i = 0; i < size; i++)
  {
      if(array[i] )
          return false; // return false at the first found

  }
  return true; //all elements checked
}

Answer 4

The way you wrote your code cannot work, for you are actually considering only the first element because of the two return statements in the if/else. Moreover, you use an assignment statement instead of a comparison.

It follows a reviewed example:

bool checkPegs(int *array, int size) {
    for (int i = 0; i < size; i++) {
        if(array[i] != 0) { return false; }
    }
    return true;
}

Keep in mind that it can be optimized and you can do the same using standard utilities, but I assume that you are learning to code and so it's worth to write it for yourself.

Answer 5

if(array[i] = 0)

That doesn't compare array[i] with 0, it assigns 0 to array[i]. You want array[i] == 0.

if(array[i] == 0)
{
    return true;
}
else
{
    return false;
}

The second issue is that you only check the first element, then return based on that. You should check every element to ensure they are non-zero:

for (int i = 0; i < size; i++)
{
    if(array[i] != 0) {
        return false;
    }
}

Finally, you don't handle the case that size is 0. In that case, you should return true.

bool checkPegs(int array[], int size)
{
    for (int i = 0; i < size; i++)
    {
        if(array[i] != 0) {
            return false;
        }
    }

    return true;
}