59-binary-search.cpp

#include <iostream>
using namespace std;

int binarySearch(int arr[], int size, int key){
    int leftIndex = 0, rightIndex=size-1, searchIndex;
    int isIncreasingRight = arr[size-1] > arr[0];
   
    cout << "isIncreasing: " << isIncreasingRight << endl;
    
    while(leftIndex <= rightIndex) {
        cout << "-----------------------------------"<<endl; 
        searchIndex=leftIndex + (rightIndex-leftIndex)/2; // same as (leftIndex+rightIndex)/2
        cout << "left at begin: "<< leftIndex << endl;
        cout << "right at begin: " << rightIndex << endl;
        cout << "SearchIndex: "<< searchIndex << endl;

        if(arr[searchIndex] == key) return searchIndex;   
        else if (arr[searchIndex]>key) isIncreasingRight ? rightIndex = searchIndex-1 : leftIndex = searchIndex+1;
        else if (arr[searchIndex]<key)  isIncreasingRight ? leftIndex = searchIndex+1 : rightIndex = searchIndex-1;
    
        cout << "left at end: "<< leftIndex << endl;
        cout << "right at end: " << rightIndex << endl;   

        cout << "-----------------------------------"<<endl;
    
    }

    return -1;
}


int main(){
    int arr1[6] = {3,7,11,13,19,27};
    cout << "Hello"<< endl;
    cout << binarySearch(arr1, 6, 27) << endl;
    return 0;
}