为什么我的向量下标超出范围？

Question

Keep getting this error "Vector subscript out of range". I'm sure its because of this part of my code. Can anyone help me see what I'm doing wrong

bool set::remove(SET_ELEMENT_TYPE removalCandidate)
{
  int subscript = positionOf(removalCandidate);
  while( (subscript < my_size) && (my_element[subscript] != removalCandidate))
  {
     subscript++;
  }
  if(subscript = -1)
  {
    if(subscript == my_size)
      return false;
    else {
      while (subscript < my_size)
      {
        my_element[subscript] = my_element[subscript + 1];
        subscript++;
      }
      my_size--;
      return true;
    }
    return false;
  }
  return 0;
}

Answer 1

You assign -1 to subscript in this if condition:

if(subscript = -1)

The intention of this code is not clear.

You will access beyond your vector boundary in this loop at the point that the first access of subscript when it is -1, , and at the end of the loop when subscript is equal to my_size - 1 .

while (subscript < my_size)
{
    my_element[subscript] = my_element[subscript + 1];
    subscript++;
}

This is because my_element[-1] is one behind the first element, and my_element[my_size] is reading one past the last element of your vector. You can change your test:

while (subscript + 1 < my_size)
{ //...

This fixes out of bounds at the end of the while loop, but you should fix the if condition to not assign to subscript .

Answer 2

while( (subscript < my_size) && (my_element[subscript] != removalCandidate) )

Unless you are trying to have unique values in the Vector you don't need the && with the second part of your conditional. You are also not removing the 'removalCandidate' because you close the loop before getting to your IF statements.

@0x499602D2 is right in that you will be checking your Vector with a subscript that is -1. So you will always be out of range.

Lastly, the subscript at the end of your while loop will equal my_size and so when referencing

my_element[subscript]

that will also be out of range every time if your Vector's size is 10 but the referencing of the Vector begins at zero. So you should reference the Vector from 0 to (my_size-1).