# Answers for "binary search c++"

13

binary search program c++

``````#include <iostream>
using namespace std;

// This program performs a binary search through an array, must be sorted to work
int binarySearch(int array[], int size, int value)
{
int first = 0,         // First array element
last = size - 1,       // Last array element
middle,                // Mid point of search
position = -1;         // Position of search value
bool found = false;        // Flag
while (!found && first <= last)
{
middle = (first + last) / 2;     // Calculate mid point
if (array[middle] == value)      // If value is found at mid
{
found = true;
position = middle;
}
else if (array[middle] > value)  // If value is in lower half
last = middle - 1;
else
first = middle + 1;          // If value is in upper half
}
return position;
}
int main ()
{
const int size = 5; // size initialization
int array[size] = {1, 2, 3, 4, 5}; // declare array of size 10
int value; // declare value to be searched for
int result; // declare variable that will be returned after binary search

cout << "What value would you like to search for? "; // prompt user to enter value
cin >> value;
result = binarySearch(array, size, value);

if (result == -1) // if value isn't found display this message
else  // If value is found, displays message
cout << "Your value is in the array.\n";

return 0;
}``````
Posted by: Guest on October-31-2020
12

binary search java

``````// Java implementation of iterative Binary Search
class BinarySearch {
// Returns index of x if it is present in arr[],
// else return -1
int binarySearch(int arr[], int x)
{
int l = 0, r = arr.length - 1;
while (l <= r) {
int m = l + (r - l) / 2;

// Check if x is present at mid
if (arr[m] == x)
return m;

// If x greater, ignore left half
if (arr[m] < x)
l = m + 1;

// If x is smaller, ignore right half
else
r = m - 1;
}

// if we reach here, then element was
// not present
return -1;
}

// Driver method to test above
public static void main(String args[])
{
BinarySearch ob = new BinarySearch();
int arr[] = { 2, 3, 4, 10, 40 };
int n = arr.length;
int x = 10;
int result = ob.binarySearch(arr, x);
if (result == -1)
System.out.println("Element not present");
else
System.out.println("Element found at "
+ "index " + result);
}
}``````
Posted by: Guest on April-02-2020
16

how to do binary search in c++ using STL

``````// BY shivam kumar KIIT
#include<bits/stdc++.h>
usind namespace std;
int main()
{
int arr[]={10,2,34,2,5,4,1};
sort(arr,arr+7);//sort array in ascending order before using binary search
binary_search(arr,arr+7,10);//return 1 as element is found
return 0;
}``````
Posted by: Guest on January-11-2021
5

binary search in c++

``````#include<iostream>
using namespace std;
int binarySearch(int arr[], int p, int r, int num) {
if (p <= r) {
int mid = (p + r)/2;
if (arr[mid] == num)
return mid ;
if (arr[mid] > num)
return binarySearch(arr, p, mid-1, num);
if (arr[mid] < num)
return binarySearch(arr, mid+1, r, num);
}
return -1;
}
int main(void) {
int arr[] = {1, 3, 7, 15, 18, 20, 25, 33, 36, 40};
int n = sizeof(arr)/ sizeof(arr[0]);
int num = 33;
int index = binarySearch (arr, 0, n-1, num);
if(index == -1)
cout<< num <<" is not present in the array";
else
cout<< num <<" is present at index "<< index <<" in the array";
return 0;
}``````
Posted by: Guest on July-20-2020
2

binary search function in c++

``````#include<iostream>
using namespace std;
int binarySearch(int arr[], int p, int r, int num) {
if (p <= r) {
int mid = (p + r)/2;
if (arr[mid] == num)
return mid ;
if (arr[mid] > num)
return binarySearch(arr, p, mid-1, num);
if (arr[mid] > num)
return binarySearch(arr, mid+1, r, num);
}
return -1;
}
int main(void) {
int arr[] = {1, 3, 7, 15, 18, 20, 25, 33, 36, 40};
int n = sizeof(arr)/ sizeof(arr[0]);
int num = 33;
int index = binarySearch (arr, 0, n-1, num);
if(index == -1)
cout<< num <<" is not present in the array";
else
cout<< num <<" is present at index "<< index <<" in the array";
return 0;
}``````
Posted by: Guest on August-13-2020
0

binary search c++

``````int binarySearch(int arr[], int l, int r, int x)
{
if (r >= l) {
int mid = l + (r - l) / 2;
if (arr[mid] == x)
return mid;
if (arr[mid] > x)
return binarySearch(arr, l, mid - 1, x);
return binarySearch(arr, mid + 1, r, x);
}
return -1;
}``````
Posted by: Guest on October-14-2021