Divide and Conquer-Returning an array - c

Question

I'm Recently going through Divide and Conquer Algorithm.
I'm able to solve the problems if the return value supposes to be some single integer.
Ex:1. Binary Search, here I just need to return 1 if found, else -1.
Ex:2. Maximum Number in an array, just need to return a single number.
But when it comes to returning an array, like when we need the whole array as output(Ex: Sorting).
I feel it difficult.
Can anyone help with the best approach?
Below is my approach for Binary Search.
#include<stdio.h>
char* Divide(int arr[],int l,int r,int key)
{
int m=(l+r)/2;
if(l==r)
{
if(key==arr[m])
return "Found";
else
return "Not Found";
}
else
{
if(key==arr[m])
return "Found";
else if(key>arr[m])
Divide(arr,m+1,r,key);
else
Divide(arr,l,m,key);
}
}
int main()
{
int arr[]={1,2,3,4,5,6,7,8};
int n=sizeof(arr)/sizeof(arr[0]);
char* result=Divide(arr,0,n-1,10);
printf("%s\n",result);
return 0;
}

Answer 1

you would have to return the values in your recursive call try
#include<stdio.h>
char* Divide(int arr[],int l,int r,int key)
{
int m=(l+r)/2;
if(l==r)
{
if(key==arr[m])
return "Found";
else
return "Not Found";
}
else
{
if(key==arr[m])
return "Found";
else if(key>arr[m])
return Divide(arr,m+1,r,key); // just returning values here
else
return Divide(arr,l,m,key); // and here would make it work
}
}
int main()
{
int arr[]={1,2,3,4,5,6,7,8};
int n=sizeof(arr)/sizeof(arr[0]);
char* result=Divide(arr,0,n-1,10);
printf("%s\n",result);
return 0;
}
check the demo at online compiler