bubble sort directional problems

I want to sort an array using bubble sort. I know it's the slowest but i have only 5-10 elements so it's fast enough. My algorithm for bubble sort works cause if I code this

Code:

void Bubble(int array[], int length, int direction)
{
	int i, j;
	
	for (i=0; i<(length-1); i++) 
	{
		for (j=0; j<(length-i-1); j++) 
		{
			if (array[j] > array[j+1])
				 Swap(&array[j], &array[j+1]);
		}
	}
}

for the array

Code:

884, 275, 470, 890, 860

i get as expected

Code:

275, 470, 860, 884, 890

I also want the user to determine in which direction the array is sorted, up or down, but here is the problem because I get a stupid response.

Code:

void Bubble(int array[], int length, int direction)
{
	int i, j;
	
	for (i=0; i<(length-1); i++) 
	{
		for (j=0; j<(length-i-1); j++) 
		{
			if (direction == 1)
				if (array[j] > array[j+1])
				   Swap(&array[j], &array[j+1]);
			else 
				if (array[j] < array[j+1]) 
					Swap(&array[j], &array[j+1]); 
		}
	}
}

but now i get this

Code:

860, 890, 470, 275, 884

and it's ming boggling why!!

Originally Posted by budala

Code:

			if (direction == 1)
				if (array[j] > array[j+1])
				   Swap(&array[j], &array[j+1]);
			else 
				if (array[j] < array[j+1]) 
					Swap(&array[j], &array[j+1]);

Hey,

the C compiler always binds the "else" to the inner-most if, so that your else is not bound to the "if (direction == 1)". Your indention however easily leads to the assumption that your code must be correct. Instead rewrite your code as follows:

Code:

			if (direction == 1)
                        {
				if (array[j] > array[j+1])
				   Swap(&array[j], &array[j+1]);
                        }
			else
                        { 
				if (array[j] < array[j+1]) 
					Swap(&array[j], &array[j+1]); 
                        }
}

- Andi -