CODEWITHSUNDEEP
csorting
user246813
user246813

Reputation: 13

Need help to solve function issue

I'm practicing my C skills by trying to code a program for rearranging array elements in ascending order by using a created function called Bubbleswap. TO fill up the array I've used the random number generator.

When I use the following code, I will get the message that Bubblesort function is missing a return value, while it shouldn't need one. And I think therefore the request to use bubbleswap function is not working properly.

//Opgave bubblesort functie

#include "toolbox.h"
#include <ansi_c.h>
#include <stdio.h>
#include <time.h>

// functies //
double bubblesort (double arrayA[], int n)
{
int  a,b,swap;

    for (a =0;a<(n - 1);a++)
    {
        for (b=0;b<(n - a - 1);b++)
        {
            if(arrayA[b]>arrayA[b+1]) // for decreasing order use < 
            {
                swap = arrayA[b];
                arrayA[b]= arrayA[b+1];
                arrayA[b+1]=swap;   
            }
        }
    }
}

// main script  //    

int main()                                      
{
    int aantal,i;                                   //variables
    double arrayA[1000],arrayB[1000]  ;
    float r;

    srand(time(NULL));                              // to start the random seeds

    printf(" Typ het aantal getallen in. \n");      //request the elements
    scanf("%d", &aantal);

    for(i=0; i<aantal;i++)                          // fill the array with random numbers
    {
        arrayA[i]=rand();
    }

    printf("Getallen in volgorde \n");        //re-arrange the numbers with the help of bubblesort
    for (i=0; i<aantal;i++)
    {
        r = bubblesort(arrayA, aantal);       //request the function bubblesort  //r =arrayA[i];
        printf("%.0f \n",  r);
    }

    getchar();
    getchar();
}

Upvotes: 1

Views: 56

Answers (4)

Najat
Najat

Reputation: 197

You need to sort the array using the bubblesort function, right? Then you don't have to return anything from the function. Because by sending the array to the function, you send the reference of it and the elements of the array will be set in the sorted order. But if you want to return anything from the function (like you wrote that you'll return a double value from the array), you must return a value of that data type. But you didn't do this. That's why the program didn't compile properly.

Upvotes: 1

Jack
Jack

Reputation: 133577

The signature of the function is the following

double bubblesort(double arrayA[], int n)

                   ^
                  arguments
         ^
        function name
  ^
 return value

So you are stating that bubblesort returns a value of type double, but there is no return statement in your code.

There are two situations in which this may happen:

  • you really intended the function to return a value but you forgot to return it (or some code path doesn't return it)
  • you chose a wrong return type for the function

In this case a function like bubblesort shouldn't return anything, given its specification, so you should change double to void to explicitly state this.

But in the line 

r = bubblesort(arrayA, aantal);       //request the function bubblesort  //r =arrayA[i];
printf("%.0f \n",  r);

you store the return value of your function bubblesort. So when changing the return value type, you also have to remove this two lines.

Upvotes: 1

coder
coder

Reputation: 12972

If I understood correctly due to your the comment //r =arrayA[i];, to accomplish that you could change:

r = bubblesort(arrayA, aantal,i);

and:

 double bubblesort (double arrayA[], int n,int i)
    {
    int  a,b,swap;

        for (a =0;a<(n - 1);a++)
        {
            for (b=0;b<(n - a - 1);b++)
            {
                if(arrayA[b]>arrayA[b+1]) // for decreasing order use < 
                {
                    swap = arrayA[b];
                    arrayA[b]= arrayA[b+1];
                    arrayA[b+1]=swap;   
                }
            }
        }
       return arrayA[i];
    }

Upvotes: 1

Lundin
Lundin

Reputation: 213872

You declared the function as

double bubblesort (double arrayA[], int n)

So the compiler expects a return value. If you don't need one, then don't declare the function that way.

Upvotes: 1

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