Lab_3

#include <stdio.h>
mergesort(int [], int, int);
merge(int [], int, int, int);
void main()
{
int a[20],n,i;
clrscr();
printf("enter the no of elements");
scanf("%d",&n);
printf("enter the array elements");
for(i=0;i<n;i++)
scanf("%d",&a[i]);
printf("\n original list");
for(i=0;i<n;i++)
printf("%4d",a[i]);
mergesort(a,0,n-1);
printf("\n sorted list");
for(i=0;i<n;i++)
printf("%4d",a[i]);
getch();
}
mergesort(int a[],int lb,int ub)
{
int mid;
if (lb<ub)
{
mid = (lb+ub)/2;
mergesort(a,lb,mid);
mergesort(a,mid+1,ub);
merge(a,lb,mid,ub);
}
return 0;
}
merge(int a[],int lb, int mid,int ub)
{
int i,j,k,c[20];
i=lb;
k=lb;
j=mid+1;

while((i<=mid) && (j<=ub))
{
if(a[i] <a[j])
{
c[k] =a[i];
k++;
i++;
}
else
{
c[k]=a[j];
k++;
j++;
}
}
while(i<=mid)
{
c[k] =a[i];
k++;
i++;
}
while(j<=ub)
{
c[k] =a[j];
k++;
j++;
}
for (i=lb;i<k;i++)
a[i]=c[i];
return;
}