Is this Binary Search working for long Array ?

Question

is this binary search program will run without problem ?
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#include<iostream>
using namespace std;

void binarysearch(int arr[],int size,int key){
int st=0,mid,last=size-1,cnt=0;
while(st<last){
mid=(st+last)/2;
//cout<<cnt++<<" "; // to check how mant times loop run
if(arr[mid]==key) {
cout<<"found";
return;
}
if(arr[mid]>key && arr[st]<key){
last=mid;
}else{
st=mid;
}
}
cout<<"not found";

}
int main(){
int arr[]={1,2,3,4,5,6,7,8,9};
int arr_size=sizeof(arr)/sizeof(arr[0]);

int key=6;

binarysearch(arr,arr_size,key);
return 0;
}

Answer 1

#include<iostream>
using namespace std;

void binarysearch(int arr[],int size,int key){
int st=0,mid,last=size-1,cnt=0;
while(st<last){
mid=(st+last)/2;
cout<<cnt++<<" ";// to check how mant times loop run
if(arr[mid]==key) {
cout<<"found";
return;
}
if(arr[mid]>key && arr[st]<key){
last=mid;
}else{
st=mid;
}
}
cout<<"not found";

}
int main(){
int arr[]={1,2,3,4,5,6,7,8,9};
int arr_size=sizeof(arr)/sizeof(arr[0]);

int key=6;

binarysearch(arr,arr_size,key);
return 0;
}

Answer 2

Martin Taylor It's a good programming exercise. And it can improve understanding of the algorithm.

Answer 3

Large array means large number of elements and its working for key 6.

Answer 4

If array is sorted in descending order binary search should work?