Write a program to merge two sorted arrays

#include <stdio.h>
#include <conio.h>
int main()
{
int arr1[10], arr2[10], arr3[20];
int i, n1, n2, m, index=0;
int index_first = 0, index_second = 0;
clrscr();
printf("\n Enter the number of elements in array1 : ");
scanf("%d", &n1);
printf("\n\n Enter the elements of the first array");
for(i=0;i<n1;i++)
{
printf("\n arr1[%d] = ", i);
scanf("%d", &arr1[i]);
}
printf("\n Enter the number of elements in array2 : ");
scanf("%d", &n2);
printf("\n\n Enter the elements of the second array");
for(i=0;i<n2;i++)
{
printf("\n arr2[%d] = ", i);
scanf("%d", &arr2[i]);
}
m = n1+n2;
while(index_first < n1 && index_second < n2)
{

if(arr1[index_first]<arr2[index_second])
{
arr3[index] = arr1[index_first];
index_first++;
}
else
{
arr3[index] = arr2[index_second];
index_second++;
}
index++;
}
// if elements of the first array are over and the second array has some elements
if(index_first == n1)
{
while(index_second<n2)
{
arr3[index] = arr2[index_second];
index_second++;
index++;
}
}
// if elements of the second array are over and the first array has some elements
else if(index_second == n2)
{
while(index_first<n1)
{
arr3[index] = arr1[index_first];
index_first++;
index++;
}
}
printf("\n\n The merged array is");
for(i=0;i<m;i++)
printf("\n arr[%d] = %d", i, arr3[i]);
getch();
return 0;
}