Thread: Sorting program

Hello,

I'm trying to write a program that sorts an array of ints.
I know i can easily find one on internet but I want to know why my program is not working.
Btw, in this exercice i don't want to use for loop, only while.

Code:

#include<unistd.h>
#include<stdio.h>

void sort(int *arr, int size);

int main(void)
{
    int ptr[4]; //Initializing the value of the ints
    ptr[0]=2;
    ptr[1]=4;
    ptr[2]=1;
    ptr[3]=3;
    sort(ptr,4); //calling the function
    int i;
    i=0;

    while(i<=3)
    {
        printf("%i",ptr[i]); // Printing the modified ptr[]
        i++;
    }
}

void sort(int *arr, int size)
{
    int b; //counter
    b=0;
    int temp; //temporary variable for storage

    while(b<size)
    {
        if(arr[b]>arr[b+1])
        {
            temp=arr[b];
            arr[b]=arr[b+1]; //swaping values
            arr[b]=temp;
        }
        else
        {
            b++; //If int in order just add 1 to b
        }
    }
}

if(arr[b]>arr[b+1] => if that's the case, b will never be incremented.
since you are comparing two neighbouring values, you will also need extra variable, that indicates, if two values were swapped.

1. before the execution of the while-loop you define an int variable int swapped = 1
2. while(b < size && swapped == 1) etc
3. the first statement in the while loop: you set swapped = 0
4. after you actually swap two variables, you set swapped = 1

the while loop will be executed as long two variables have been swapped. if no variables have been swapped, all values are already sorted and the program will continue after the while-loop.