pointers with array

This is a discussion on pointers with array within the C Programming forums, part of the General Programming Boards category; Here's my program. Can anyone tell me how to use pointer points to the data in ascending and other pointers ...

  1. #1
    Registered User
    Join Date
    Feb 2002
    Posts
    11

    pointers with array

    Here's my program.

    Can anyone tell me how to use pointer points
    to the data in ascending and other pointers
    point to the data in descending, but keep the
    original?

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

    #define SIZE 10

    int *getNum(int *, int);
    void selectSort(int *, int *);
    void printSort (int *, int *);

    int main(void)
    {
    int num[SIZE];
    int *pLast;

    pLast = getNum(num, SIZE);
    selectSort(num, pLast);
    printSort (num, pLast);

    return 0;
    }

    /******************************* GET NUMBER *********************/

    int *getNum(int *pNum, int size)
    {
    int readNum = 0;
    int result, count = 1;

    int *pFill = pNum;

    do
    {
    printf("\nPlease enter number %d: ", count);
    result = scanf("%d", pFill);
    count++;

    if(result == 1)
    {
    pFill++;
    readNum++;
    }

    }while(result == 1 && readNum < size);
    printf("\n\n");

    return(--pFill);

    }

    /******************************* SELECT SORT *********************/

    void selectSort(int *pNum, int *pLast)
    {
    int *smallest(int *pNum, int *pLast);
    void swap(int *current, int *smallest);

    int *pi, *pSmall;

    for(pi = pNum; pi < pLast; pi++)
    {
    pSmall = smallest(pi, pLast);
    swap(pi, pSmall);
    }
    return;
    }

    /*------------------------------ SMALLEST -----------------------*/

    int *smallest(int *pNum, int *pLast)
    {
    int *pLooker, *pSmallest;

    for(pSmallest = pNum, pLooker = pNum+1; pLooker <= pLast; pLooker++)
    {
    if(*pLooker < *pSmallest)
    {
    pSmallest = pLooker;
    }
    }
    return(pSmallest);
    }

    /*------------------------------ SWAP -----------------------*/

    void swap(int *p1, int *p2)
    {
    int temp;

    temp = *p1;
    *p1 = *p2;
    *p2 = temp;

    return;
    }

    /******************************* PRINT DATA *********************/

    void printSort(int *pNum, int *pLast)
    {
    int numPrint;
    int *pPrint = pNum;

    for(pPrint = pNum, numPrint = 0; pPrint <= pLast; numPrint++, pPrint++)
    {
    printf("%d ", *pPrint);
    }
    printf("\n\n");

    return;
    }

  2. #2
    Unregistered
    Guest

    Talking

    This sounds like a problem out of the C book I teach from!!

    To things I see imediately:

    printf("\nPlease enter number %d: ", count);
    result = scanf("%d", pFill);

    Watch how you enter numbers with pointers. you should change this line.


    Second,

    swap(pi, pSmall);

    this call is wrong


    Mr. C.

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