Why is this implementation of merge sort not working?

I am missing something embarrassing element in my Merge Sort implementation:

# include <math.h>
# include <stdio.h>

int temp[10];

void merge_sort(int *indices, int x, int z);
void m_merge(int *indices, int x, int y, int z);


void merge_sort(int *indices, int x, int z )
{
        int y;
        if(x<z){
                y = (x+z)/2;
                merge_sort(indices,x,y);
                merge_sort(indices,y+1,z);
                my_merge(indices,x,y,z);
        }
}

void my_merge(int *indices, int x, int y, int z)
{
        int mark1=x, mark2=y+1;
        int cnt=0;

        while(mark1 <= y && mark2 <= z){
                if (indices[mark1] < indices[mark2])
                        temp[cnt++] = indices[mark1++];
                else
                        temp[cnt++] = indices[mark2++];
        }
        while(mark1 <= y)
                temp[cnt++] = indices[mark1++];

        while(mark2 <= z)
                temp[cnt++] = indices[mark2++];

}

int main(int argc, char **argv)
{
        int arr[] = {1,5,8,7,4,30,-87,100,200,300};
        int i; 
        merge_sort(arr,0,9);

        for(i=0;i<=9;i++)
                printf(" %d \n  ",temp[i]);

        return 0;
}

      

Why doesn't it work as it should? I checked and checked again but I am not getting a sorted array. What am I missing here?

This is what I get: 1 5 8 7 4 30 -87 100 200 300

You can vote, but I'm very confused myself to ask this here.

+2


source to share


1 answer


my_merge () concatenates numbers in temp [], but never copies them back to indices []. Copy them back to the correct location and it should work.



+1


source







All Articles