Sir, i am having dought in find() function

#1

#include
#include
using namespace std;
int main()
{
int arr[]={20,30,40,40,40,40,50,100,1100};
int n=sizeof(arr)/sizeof(int);
int key;
cin>>key;
bool present=binary_search(arr,arr+n,key);
if(present)
{
cout<<“present”<<endl;
}
else
{
cout<<“absent”<<endl;
}
auto lb=lower_bound(arr,arr+n,key);
if((lb-arr)==n)
{
cout<<“not present”<<endl;

}
else
{
	cout<<(lb-arr)<<endl;
}
return 0;

}

sir this code working properly but when i am invin key as 12 it is showing 0 and if i am giving 444444 then is is giving me element is not present…
i want to say that this code is giving different answer for small number like 12,13 and giving right answer for big numbers like 122222or 4444, why so sir.

#2

hello @Abhishmu5

if key is not present in array then lower bound return an iterator whose value is greater than key.
for ex-> key -> 4 , array-> 2 , 3, 9 , 10 ,12
here lower bound of 4 return iterator for 9 and clearly itr for 9 -array will not be n. so ur logic will fail.

#3

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