Thread: Completing this program

Code:

#include <stdio.h>
#include <conio.h>
void swap(int *, int *);
void bubble(int [], int);
main(){
       int a[] = {7, 3, 66, 3, -5, 22, -77, 2};
       
       printf("I will arrange these numbers in order");
       bubble(a[], n);
       printf("%d", a[]);
       getch();
       return 0;
}

void swap(int *p, int *q)
{
     int tmp;
     
     tmp = *p;
     *p = *q;
     *q = tmp;
}

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

That's my program..the problem is that I don't know what to put in the main. My brain just SHUT DOWN and it's not functioning well.. :blush:
Can anyone please help?

Never Mind!! I Already Figured Out My Problem... Please Don't Reply To This Thread Anymore...

>Can anyone please help?
Be careful what you wish for. Let's start by shredding your code.

>#include <conio.h>
This is totally not needed. Get rid of it and use a standard solution instead. I'll come back to this shortly.

>void swap(int *, int *);
>void bubble(int [], int);
Others may not agree, but this is your interface, and it needs to be informative. That means naming your parameters. swap and bubble are both common names, so a prefix to avoid ambiguity is a good idea.

>main(){
The latest C standard prohibits the implicit int that you're using here. Even before C99 it was poor style, so you should consider using a conventional definition of main:

Code:

int main ( void )
{
    return 0;
}

>printf("I will arrange these numbers in order");
What numbers? I'm a user and I'm incredibly stupid. Spell it out for me.

>bubble(a[], n);
Where are you getting n? Also, the brackets aren't needed for a function argument, just the array name.

>printf("%d", a[]);
This won't print anything useful, and it's actually pretty unsafe. Then again, it won't compile because of the brackets so what you have here is the ultimate security feature.

>getch();
This isn't needed. If you're willing to force the user to hit Return instead of any key then you can use getchar and not suffer from a non-portable program. Since "Press any key" usually results in the user hitting Return anyway, not much is lost.

>void bubble(int a[]; int n)
Comma?

>for(i=0; i < n-1; ++i)
> for(j = n-1; i<j; --j)
> if(a[j-1] > a[j])
> swap(&a[j-1], &a[j]);
This is strictly my personal preference, but if the body of a conditional or loop is longer than one line (including comments), I use braces. That would turn your loop into this:

Code:

for(i=0; i < n-1; ++i) {
    for(j = n-1; i<j; --j) {
        if(a[j-1] > a[j])
            swap(&a[j-1], &a[j]);
    }
}

Finally, consistency in your formatting is of the utmost importance. Even if you don't care, take the time to make sure that your formatting is consistent throughout the program.

Here's a potential reworking so that you can compare and contrast:

Code:

#include <stdio.h>

#define length(a) (sizeof (a) / sizeof *(a))

void jsw_swap ( int *a, int *b );
void jsw_bubblesort ( int array[], int n );
void jsw_display ( int array[], int n );

int main ( void )
{
    int a[] = {7, 3, 66, 3, -5, 22, -77, 2};

    printf ( "Original: " );
    jsw_display ( a, length ( a ) );
    jsw_bubblesort ( a, length ( a ) );
    printf ( "Sorted: " );
    jsw_display ( a, length ( a ) );
    getchar();

    return 0;
}

void jsw_swap ( int *a, int *b )
{
    int save = *a;
    *a = *b;
    *b = save;
}

void jsw_bubblesort ( int array[], int n )
{
    int i, j;

    for ( i = 0; i < n - 1; ++i ) {
        for ( j = n - 1; i < j; --j ) {
            if ( array[j - 1] > array[j] )
                jsw_swap ( &array[j - 1], &array[j] );
        }
    }
}

void jsw_display ( int array[], int n )
{
    int i;

    for ( i = 0; i < n; ++i )
        printf ( "%d ", array[i] );

    printf ( "\n" );
}