Question

Write a program in C++ to read an array of sorted integers. Search for a value using binary
search method. If the element is found, print its location else print element not found.
Computer Science 65
ii. Name the header file to which the following built in functions belong to :-
a) cos() b) strcpy()
ii. Difference between:-
a) Global and local variable
b) Call by value and Call by reference

Answer 1

#include <iostream>

using namespace std;

int binarySearch(int, int*, int);

int main()
{
int *array;
int size;
int value;
cout << "Enter size of array: ";
cin >> size;
array = new int[size];
for (int i = 0; i < size; i++)
{
cin >> array[i];
}
cout << "Enter value for search: ";
cin >> value;
int index = binarySearch(size, array, value);
if (index >= 0)
cout << "Element is found, its location " << index << endl;
else
cout << "Element not found" << endl;
return 0;
}

int binarySearch(int size, int* array, int value) {
int first = 0;
int last = size;
while (last > first)
{
int mid = (last + first) / 2;
if (array[mid] == value)
return mid;
if (value > array[mid])
first = mid + 1;
else
last = mid - 1;
}
return -1;
}