Bubble sort in C

I’m writing this for someone special. Hope this would help. This is at the same time a review of my past lessons. Assuming i,j and tmp are defined as integers, num[] as an array of integers, and SIZE as a constant.

for (i = 0; i < SIZE - 1; ++i)
        for (j = SIZE - 1; j < i; --j)
                if (num[j-1] > num[j]) {
                        tmp = num[j-1];
                        num[j-1] = num[j];
                        num[j] = tmp;
                }

Here is another way of doing it. This is a demo on how the function works on a particular array of integers. a[] is the array of integers while n is the size of the array.

void swap(int *, int *);
	
void bubble(int a[], int n)
{
        int i, j;
	
        for (i = 0; i < n - 1; ++i)
                for (j = n - 1; j > i; --j)
                        if (a[j-1] > a[j])
                                swap(&a[j-1], &a[j]);
}
	
void swap(int *p, int *q)
{
        int tmp;
	
        tmp = *p;
        *p = *q;
        *q = tmp;
}

If you are keen enough to observe, check that we can use the swap arguments presented below.

swap(a + i, a + j);

Getting the idea? Pointer arithmetic! God bless and good day.