Question

im having trouble programming bubblesort in java. it only goes through the array once. help!

Answer 1

public static int[] bubbleSort(int[] a){
int temp=0;
boolean swapped=true;
int num=a.length;
int sorted=0;
while(sorted<a.length){
while(swapped){
for(int i=0;i<num-1;i++){
if (a[i]>a[i+1])
{
temp=a[i];
a[i]=a[i+1];
a[i+1]=temp;
}
else
swapped=false;
}
num--;//invariant(?) and that numb is in place
sorted++;
}
//num--;
//sorted++;
}
return a;

}

Answer 2

Walk through your code with your test data, know what your variables are, and you'll see the problem in a couple of swaps.