MergeSort sorting algorithm written in C with recursive functions.

MergeSort

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

void mergesort(int a[],int low,int high);
void merge(int a[], int low, int high);

int main()
{
    int a[40],fin,i;
    printf("ingrese dim\n");
    scanf("%d",&fin);
    for(i=0; i<fin; i++){
        printf("ingr valor\n");
        scanf("%d",&a[i]);
    }
    mergesort(a, 0, fin-1);
    printf("\n el vector ordenado por merge");
    for(i=0; i<fin; i++){
        printf("\n %d",a[i]);
    }
    return 0;
}



void mergesort(int a[],int low,int high){
    int aux[40],i;
    if (low<high){
        //divide
        mergesort(a,low,(low+high)/2);
        mergesort(a,(low+high)/2+1,high);
        //combina
        merge(a, low, high);
    }
    return;
}

void merge(int a[], int low, int high){
    int m1=0;
    int m2=(low+high)/2-low+1;
    int i, aux[40]={0};
    for ( i=0; i<high-low+1; i++)
        aux[i]=a[low+i];

    for( i=0; i<high-low+1; i++){
        if(m2 <= high-low)
            if(m1 <= (low+high)/2 -low)
                if(aux[m1] > aux[m2])
                    a[i+low] = aux[m2++];
                else
                    a[i+low] = aux[m1++];
            else
                a[i+low]=aux[m2++];
        else
            a[i+low]=aux[m1++];
    }
    return;
}