Binary Search in C

#include<stdio.h>

int BinarySearch(int arr[],int l, int r,int num){
    printf("Entered Binary Search Function\n");
    int mid=0;
    printf("%d %d\n",l,r);
    if(l<=r){
        mid=l+(r-l)/2;
        printf("%d\n",mid);
        if(arr[mid]==num){
            return 1;
        }
        else if(arr[mid]<num){
            return BinarySearch(arr,mid+1,r,num);
        }
        else{
            return BinarySearch(arr,l,mid-1,num);
        }
    }
    return 0;
}

int main()
{
    int arr[] = {4,8,9,10,19,45};
    int num=0;
    printf("Enter Number to be searched\n");
    scanf("%d",&num);
    int r = sizeof(arr)/sizeof(int);
    //printf("%d",r);
    int res=BinarySearch(arr,0,r-1,num);
    if(res==1)
        printf("\nNumber Found\n");
    else
        printf("\nNumber Not Found\n");
    return 0;
}