Merge Sort

This is a discussion on Merge Sort within the C Programming forums, part of the General Programming Boards category; Sorry... but I need help with a problem I have I'm writing a Merge Sort for a class presentation but ...

  1. #1
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    Merge Sort

    Sorry... but I need help with a problem I have I'm writing a Merge Sort for a class presentation but I'm having a problem running it.
    Code:
     
    #include<stdio.h>
    #include<stdlib.h>
    #include<time.h>
    #define SIZE 10
    
    
    void mergeSort(int set[] , int length);
    void sortSubArray(int set[] , int low , int high);
    void merge(int set[] , int left , int middle1 , int middle2 , int right);
    void displayElements(int set[] , const int length);
    void displaySubArray(int set[] , int left , int right);
    
    
    int main()
    {
        int set[SIZE];
        int i;
        srand(time(NULL));
    
    
        for(i = 0; i < SIZE; i++)
        {
            set[i] = 10 + rand() % 99;
        }
    
    
        printf("Unsorted array: \n");
        displayElements(set , SIZE);
        printf("\n\n");
        mergeSort(set , SIZE);
        printf("Sorted array:\n");
        displayElements(set , SIZE);
        system("PAUSE");
        return 0;
    }
    
    
    void mergeSort(int set[] , int length)
    {
        sortSubArray(set , 0 , length - 1);
    }
    
    
    void sortSubArray(int set[] , int low , int high)
    {
        int middle1 , middle2;
    
    
        if((high - low) >= 1)
        {
            middle1 = (low + high) / 2;
            middle2 = middle1 + 1;
    
    
            printf("split:   ");
            displaySubArray(set , low , high);
            printf("\n                  ");
            displaySubArray(set , middle2 , high);
            printf("\n\n");
    
    
            sortSubArray(set , low , middle1);
            sortSubArray(set , middle2 , high);
    
    
            merge(set , low , middle1 , middle2 , high);
        }
    }
    
    
    void merge(int set[] , int left , int middle1 , int middle2 , int right)
    {
        int leftIndex = left;
        int rightIndex = middle2;
        int combinedIndex = left;
        int tempArray[SIZE];
        int i;
    
    
        printf("merge:   ");
        displaySubArray(set , left , middle1);
        printf("\n                   ");
        displaySubArray(set , middle2 , right);
        printf("\n");
    
    
        while(leftIndex <= middle1 && rightIndex <= right)
        {
            if(set[leftIndex] <= set[rightIndex])
            {
                tempArray[combinedIndex++] = set[leftIndex++];
            }
            else
            {
                tempArray[combinedIndex++] = set[rightIndex++];
            }
        }
    
    
        if(leftIndex == middle2)
        {
            while(rightIndex <= right)
            {
                tempArray[combinedIndex++] = set[rightIndex++];
            }
        }
        else
        {
            while(leftIndex <= middle1)
            {
                tempArray[combinedIndex++] = set[leftIndex++];
            }
        }
    
    
        for(i = left; i <= right; i++)
        {
            set[i] = tempArray[i];
        }
        printf("          ");
        displaySubArray(set , left , right);
        printf("\n\n");
    }
    
    
    void displayElement(int set[] , const int length)
    {
        displaySubArray(set , 0 , length - 1);
    }
    
    
    void displaySubArray(int set[] , int left , int right)
    {
        int i;
    
    
        for(i = 0; i < left; i++)
        {
            printf(" ");
    
    
            for(i = left; i <= right; i++)
            {
                printf("%d" , set[i]);
            }
        }
    }
    Sorry if that's too long or complicated but the problem is actuall with the displayElement procedure. (I reference it twice in main). I keep receiving a linker error wich relates to that function and I can't understand why. If anyone has the time could they help me out please. I'm in no rush , so no need to put yourself through any trouble.

  2. #2
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    So... post the errors you're getting... "a linker error" is about as nebulous as saying "it doesn't work"...

    We're gonna need real information if you want our help.

  3. #3
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    1>Merge Sort Demonstration.obj : error LNK2028: unresolved token (0A000012) "void __cdecl displayElements(int * const,int)" (?displayElements@@$$FYAXQAHH@Z) referenced in function "int __cdecl main(void)" (?main@@$$HYAHXZ)


    1>Merge Sort Demonstration.obj : error LNK2019: unresolved external symbol "void __cdecl displayElements(int * const,int)" (?displayElements@@$$FYAXQAHH@Z) referenced in function "int __cdecl main(void)" (?main@@$$HYAHXZ)

    Those 2 errors unresolved symbol and unresolved token , not sure what it means.

  4. #4
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    Referring to message #1 ...
    Compare line 11, line 33 and line 127 ... notice anything?

  5. #5
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    you have a name mismatch for your function. displayElement vs displayElements

  6. #6
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    Wow, I missed that. Thank you guys

  7. #7
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    Quote Originally Posted by tsmith94 View Post
    Wow, I missed that. Thank you guys
    That's why we pay attention to compiler and linker errors... 99 of 100 times the error message leads us directly to the problem. In this case the fact that it could not find the displayelements() function told me you'd never defined it, even though you had declared it... most likely cause? Typos.

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