Question

I’m looking to implement a bubble sort. I have the following code that I wrote, which uses a for loop inside of a do loop. How can I make this into a bubble sort that uses two for loops?

Here’s my code:

do {
    switched = false;
    for (int i = 1; i < size; i++) {
        if (a[i] < a[i-1]) {
            int temp = a[i];
            a[i] = a[i-1];
            a[i-1] = temp;
            switched = true;
        }
    }
} while (switched);

(This is tagged homework, but this is studying for the final exam, not actual homework.)

Answer 1

Because you know the last element in the list will always be sorted (since it bubbled up to the top) you can stop there.

for(int x = size; x >= 0; x--) {
    bool switched = false;
    for(int i = 1; i < x; i++) {
        if(blah) {
            // swap code here
            switched = true;
        }

    }
    if(!switched) break; // not the biggest fan of this but it gets the job done
}