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Pointers and Sorting Array by Even and Odd numbers

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taikoprogrammer taikoprogrammer is offline

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Pointers and Sorting Array by Even and Odd numbers

Aug 4th, 2009

Hi Everyone,

I need some help. So I am given this code and I have to make the functions for revArray, *reveElement, and evenOdd. So far I have figured out how to reverse the Array and print it. But I'm having some trouble sorting the array. I'm supposed to put the even numbers first then the odd numbers last in the array. But i can't figure out how... Any tips, hints, and help would be much appreciated. Thank you!

Given:

 Help with Code Tags 
 C Syntax (Toggle Plain Text) 
#include <stdio.h>
#include <stdlib.h>
#define N 9
 
 
/* MAIN */
int main(int argc, char **argv) 
{
 
             /* Load the array with numbers */
           int a[N];
           int idx;
           int *p = a;
           while(p < a + N) *p++ = a + N - p;
           printf("Original: ");
           p = a; while(p < a + N) printf("%2d ",*p++); 
 
        /* Part A: Reverse the array */
           revArray(a);
           printf("\nReversed: ");
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");
 
        /* Part B: Return elements in reverse order */
           printf("Original: ");
           for (idx = 0; idx < N; idx++) {
                  printf("%2d ",*revElement(a));
           }
           printf("\n");
 
        /* Part C: Put even numbers first, odd numbers last in the array.  Order of 
           the elements is not important as long as all evens are before first odd */
           printf("Even:     ");
           evenOdd(a);
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");
 
 
           system("pause");
           exit(0);
        }
#include <stdio.h>
#include <stdlib.h>
#define N 9
        
        
/* MAIN */
int main(int argc, char **argv) 
{

             /* Load the array with numbers */
           int a[N];
           int idx;
           int *p = a;
           while(p < a + N) *p++ = a + N - p;
           printf("Original: ");
           p = a; while(p < a + N) printf("%2d ",*p++); 
               
        /* Part A: Reverse the array */
           revArray(a);
           printf("\nReversed: ");
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");

        /* Part B: Return elements in reverse order */
           printf("Original: ");
           for (idx = 0; idx < N; idx++) {
                  printf("%2d ",*revElement(a));
           }
           printf("\n");
            
        /* Part C: Put even numbers first, odd numbers last in the array.  Order of 
           the elements is not important as long as all evens are before first odd */
           printf("Even:     ");
           evenOdd(a);
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");
           

           system("pause");
           exit(0);
        }

My Code:

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 C Syntax (Toggle Plain Text) 
 
#include <stdio.h>
#include <stdlib.h>
#define N 9
 
void revArray(int *p);
int *revElement(int *p);
void evenOdd(int *p);
 
 
/* MAIN */
int main(int argc, char **argv) 
{
 
             /* Load the array with numbers */
           int a[N];
           int idx;
           int *p = a;
           while(p < a + N) *p++ = a + N - p;
           printf("Original: ");
           p = a; while(p < a + N) printf("%2d ",*p++); 
 
        /* Part A: Reverse the array */
           revArray(a);
           printf("\nReversed: ");
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");
 
        /* Part B: Return elements in reverse order */
           printf("Original: ");
           for (idx = 0; idx < N; idx++) {
                  printf("%2d ",*revElement(a));
           }
           printf("\n");
 
        /* Part C: Put even numbers first, odd numbers last in the array.  Order of 
           the elements is not important as long as all evens are before first odd */
           printf("Even:     ");
           evenOdd(a);
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");
 
 
           system("pause");
           exit(0);
        }
 
 
         void revArray(int *p) 
         {
 
         int arr[N], i;
 
 
         int *s = p;
 
         for(i = N-1; i >=0; --i)
 
         {
 
         arr[i] = *p++;
 
         }
 
         for(i = 0; i < N; ++i)
 
         {
 
         *(s+i) = arr[i];
         }
         return;
 
 
         }
 
         int *revElement(int *p) 
         {
 
         static int idx2 = N;
 
         idx2 = --idx2;
 
         return p + idx2;
 
         }
 
         /*Sorting Array putting even numbers first, then odd. I can't figure out how to do this???*/
         void evenOdd(int *p)
 
         {
         int b[N],j=0,c[N],k=0;
         int arr[N], i;
 
         for(i = 0; i < N; ++i)
 
         {
 
         if (arr[N] %2==0)
 
         {
         b[j]=arr[i];
         j++;
         }
         else if (arr[N] %2 !=0)
         {
 
         c[k]=arr[i];
         k++;
         }
         }
         }
#include <stdio.h>
#include <stdlib.h>
#define N 9
        
void revArray(int *p);
int *revElement(int *p);
void evenOdd(int *p);
        
        
/* MAIN */
int main(int argc, char **argv) 
{

             /* Load the array with numbers */
           int a[N];
           int idx;
           int *p = a;
           while(p < a + N) *p++ = a + N - p;
           printf("Original: ");
           p = a; while(p < a + N) printf("%2d ",*p++); 
               
        /* Part A: Reverse the array */
           revArray(a);
           printf("\nReversed: ");
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");

        /* Part B: Return elements in reverse order */
           printf("Original: ");
           for (idx = 0; idx < N; idx++) {
                  printf("%2d ",*revElement(a));
           }
           printf("\n");
            
        /* Part C: Put even numbers first, odd numbers last in the array.  Order of 
           the elements is not important as long as all evens are before first odd */
           printf("Even:     ");
           evenOdd(a);
           p = a; while(p < a + N) printf("%2d ",*p++);
           printf("\n");
           

           system("pause");
           exit(0);
        }


         void revArray(int *p) 
         {

         int arr[N], i;


         int *s = p;

         for(i = N-1; i >=0; --i)

         {

         arr[i] = *p++;

         }

         for(i = 0; i < N; ++i)

         {

         *(s+i) = arr[i];
         }
         return;


         }
         
         int *revElement(int *p) 
         {

         static int idx2 = N;

         idx2 = --idx2;

         return p + idx2;

         }

         /*Sorting Array putting even numbers first, then odd. I can't figure out how to do this???*/
         void evenOdd(int *p)

         {
         int b[N],j=0,c[N],k=0;
         int arr[N], i;

         for(i = 0; i < N; ++i)

         {

         if (arr[N] %2==0)

         {
         b[j]=arr[i];
         j++;
         }
         else if (arr[N] %2 !=0)
         {
    
         c[k]=arr[i];
         k++;
         }
         }
         }

Last edited by taikoprogrammer; Aug 4th, 2009 at 7:39 pm.

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Join Date: Jun 2008

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Hiroshe

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Re: Pointers and Sorting Array by Even and Odd numbers

Aug 4th, 2009

Pass through the input array twice. The first time, if the number is even, put it in the output array. The second time, if the number is odd, put it in the output array.

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