C program to merge two sorted arrays. Array Union

//C/C++/C Plus Plus program to merge two sorted arrays
//C/C++/C Plus Plus program to find union of two sorted arrays
#include<iostream>
using namespace std;
#include<stdio.h>

int arrayIntersection(int arr1[],int arr2[],int n1,int n2);
int main()
{
cout<<"manin()\n";
int arr1[]={1,2,3,4,5};
int arr2[]={3,5,7,8,9};
int n1; n1=sizeof(arr1)/sizeof(arr1[0]);
int n2; n2=sizeof(arr2)/sizeof(arr2[0]);
arrayIntersection(arr1,arr2,n1,n2);
return 0;
}
int arrayIntersection(int arr1[],int arr2[],int n1,int n2)
{
int i=0,j=0;
while(i<n1 && j<n2)//while any of the array has elt
{
if(arr1[i]<arr2[j])
{
printf("%d",arr1[i]);
i++;
}
else if(arr2[j]<arr1[i])
{
printf("%d",arr2[j]);
j++;
}
else //arr[i]==arr[j]
{
printf("%d",arr2[j]);
i++;
j++;
}
}
while(i<n1)
printf("%d",arr1[i++]);
while(j<n2)
printf("%d",arr2[j++]);

cout<<endl;
}
//output
//12345789