Thread: Bubble Sort Code Problem...

Im not sure why this bubble sort code isn't working at all, could someone give me a hint ?
Help would be much appreciated. Thanks.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>

int array[2];
int temp[2][2];

int checkint(char s[]) //Checks if string is purely numerical
{
	int length = strlen(s); // Define string length
	for (int i = 0; i < length; i++) // For each character
	{
		if (isdigit(s[i])); // If numerical, then do nothing
		else return 0; //If not, then return 0
	}
	return 1;
}

static void bubble_sort(int r[], int y)
{
	int i, j, temp;
	for (i = 0; i < y-1; i++);
	for (j = 0; j < y-i-1; j++);
	if (r[j] > r[j + 1])
	{
		temp = r[j];
		r[j] = r[j + 1];
		r[j + 1] = temp;
	}
}

int main(int argc, char *argv[])
{
	int temp = (argc - 2);
	array[temp];
	if(argc < 2)  //Check if enough arguments have been supplied
	{
		printf("Too few arguments for this program.\n");
		exit(EXIT_FAILURE); //If not then exit
	}
	else 
	{
		for (int i = 1; i < argc; i++) //For every argument provided (excluding 0)
		{
			int ans = atoi(argv[i]); //Find the int equivalent
			int var = (i-1);
			array[var] = ans; //Store it in the array
		}
		
		bubble_sort(array, argc);
		for (int a = 0; a < argc-1; a++)
			printf("%d ", array[a]);
		printf("\n");
		
	}
	// Exit indicating success
	exit(EXIT_SUCCESS);
    return 0;
}

Your belief that "array[temp]" does anything at all is misguided.

You appear to be lying to your bubble_sort function about how many numbers are in your array (is it temp or argc?).

Im a little confused with arrays, do they have to be initialized to a certain size before you can use them ? That is all I was trying to achieve with the array[temp] line. And there should be argc-1 numbers in the array, because argc returns a count of the arguments starting at 1 (or so I believe), but arrays start counting at 0.

Originally Posted by h4rrison.james

Im a little confused with arrays, do they have to be initialized to a certain size before you can use them ?

Yes. And once you type "array[2]" then you've had your chance and blew it, as arrays cannot be resized later. And if it was a declaration then naturally it would have to have a type in front of it. (You could, of course, redeclare a new array with the same name, hiding the one in global scope. But then you would never use the global array, so you might as well not have it anymore.)

Originally Posted by h4rrison.james

That is all I was trying to achieve with the array[temp] line. And there should be argc-1 numbers in the array, because argc returns a count of the arguments starting at 1 (or so I believe), but arrays start counting at 0.

If you type "myprogram 1 2 3 4 5 6 7 8", then argc is 9 (there are nine total arguments, the name of the program and the eight numbers). So you were "declaring" an array with 7 elements, filling in 8 numbers, and telling bubble_sort to sort 9 numbers.

Thanks for your help guys, you cleared up my understanding alot. Also I found that the two for statements in the bubble_sort functions had ";" after them, killing the loop, so I've got it working now