Print all possible combinations of r elements in a given array of size n

#include<stdio.h>
 int data[30];
void fun(int arr[],int i,int N,int r,int index)
{
int j;
if(r==index)
{
for(i=0;i<r;i++)
{
printf("%d",data[i]);
}
printf("\n");
return;
}
for(j=i;j<N;j++)
{
data[index]=arr[j];
fun(arr,j+1,N,r,index+1);
}
}

int main()
{
 int arr[5]={1,2,3,4,5};
 int r=3;
 fun(arr,0,5,r,0);
 return 0;
}

http://www.geeksforgeeks.org/print-all-possible-combinations-of-r-elements-in-a-given-array-of-size-n/