C code for Merge Sort.There are no compilation errors but the program becomes unresponsive after taking input.please help

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

/* Merge Function for merging two subarrays*/
void Merge(int a[],int r,int lba,int b[],int s,int lbb,int c[],int lbc)
{
    int na=lba,nb=lbb,ptr=lbc,uba=lba+r-1,ubb=lbb+s-1,k;
    while(na<=uba && nb<=ubb)
    {
                  if(a[na]<b[nb])
                  {
                                 c[ptr]=a[na];
                                 ptr=ptr+1;
                                 na=na+1;
                  }
                  else
                  {
                                 c[ptr]=b[nb];
                                 ptr=ptr+1;
                                 nb=nb+1;
                  }
    }
    if(na>uba)
    {
              for(k=0;k<=ubb-nb;k++)
              c[ptr+k]=b[nb+k];
    }
    else
    {
        for(k=0;k<=uba-na;k++)
        c[ptr+k]=a[na+k];
    }
    return;
}

/*MergePass Function */
void MergePass(int a[],int n,int l,int c[])
{
     int q,s,r,lb,j;
     q=(int)(n/2*l);
     s=2*l*q;
     r=n-s;
     for(j=1;j<=q;j++)
     {
                     lb=(2*j-2)*l;
                     Merge(a,l,lb,a,l,lb+l,c,lb);
     }
     if(r<=l)
     {
             for(j=1;j<=r;j++)
             c[s+j]=a[s+j];
     }
     else
     {
             Merge(a,l,s+1,a,r,l+s+1,c,s+1);
     }
     return;
}

/*MergeSort function*/
void MergeSort(int a[],int n)
{
     int l,c[100];
     for(l=1;l<n;l=4*l)
     {
                       MergePass(a,n,l,c);
                       MergePass(c,n,2*l,a);
     }
}

/*Main (for getting input)*/
main()
{
      int i,a[100],n;
      printf("Enter the no. of elements\n");
      scanf("%d",&n);
      printf("Enter the array elements one by one\n");
      for(i=0;i<n;i++)
      scanf("%d",&a[i]);

      MergeSort(a,n);/*Call to MergeSort*/

      printf("Array after sorting using MergeSort Procedure\n");
      for(i=0;i<n;i++)
      printf("%d\t",a[i]);
      getch();
}