Iterate and delete

3 February 2005

Every once in a while, I stumble across really elegant solutions (in code) to common problems. Iterate and delete is one of those problems. How do you process an array of elements, and delete any that shouldn’t be there, without leaving the iteration? It’s assumed that the order of the elements is inconsequential.

Dierk Ohlerich provides the following solution:

struct element {
    int data;
    bool selected;
};

struct element *array;
int count;

for(int i = 0; i < count;)
{
    if(array[i].selected)
    {
        count--;
        array[i] = array[count];
    }
    else
    {
        i++;
    }
}

Sometimes, code is just sexy.

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