IP-19.c

Metadata

• Author — Amit Dutta
• Last updated — 03 Jan 2026
• License — MIT License (See the LICENSE file for details)

Problem Statement

Problem Statement

Write a C program that includes a user-defined function named binarySearch with the signature int binarySearch(int arr[], int size, int target);. The function should perform a binary search on a sorted array of integers and return the index of the target element if found, and -1 otherwise.

Source Code

View on GitHub Download Raw

Printing the code

To print this file, open it on GitHub and click Raw before printing, or use the Download Raw button above and print directly from that page.

#include <stdio.h>

int inputArray(int[], int);
// void sortArray(int[], int);
int binarySearch(int[], int, int);

int main()
{
    int size;
    printf("How many element do you want to enter: ");
    scanf("%d", &size);
    int arr[size];
    int target = inputArray(arr, size);
    // sortArray(arr, size); // If needed
    int index = binarySearch(arr, size, target);
    if (index != -1)
    {
        printf("\nElement %d is found at index %d.", target, index);
    }
    else
    {
        printf("\nElement %d is not found.", target);
    }
    return 0;
}

int inputArray(int arr[], int size)
{
    int i, target;
    for (i = 0; i < size; i++)
    {
        printf("Enter element for position %d: ", i);
        scanf("%d", &arr[i]);
    }
    printf("\nEnter the target element: ");
    scanf("%d", &target);
    return target;
}

/* void sortArray(int arr[], int size)
{    
    // using Bubble Sort...

    int tempArr[size], i, j, temp;
    printf("\nBefore Sorting:\n[");
    for (i = 0; i < size; i++)
    {
        printf("%d", arr[i]);
        if (i != size - 1)
        {
            printf(", ");
        }
    }
    printf("]\n");
    for (i = 0; i < size - 1; i++)
    {
        for (j = 0; j < size - i - 1; j++)
        {
            if (arr[j] > arr[j + 1])
            {
                temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
    printf("\nAfter Sorting:\n[");
    for (i = 0; i < size; i++)
    {
        printf("%d", arr[i]);
        if (i != size - 1)
        {
            printf(", ");
        }
    }
    printf("]\n");
}
*/

int binarySearch(int arr[], int size, int target)
{
    int low = 0;
    int high = size - 1;
    int mid;
    while (low <= high)
    {
        mid = low + ((high - low) / 2);
        if (arr[mid] == target)
        {
            return mid;
        }
        else if (arr[mid] > target)
        {
            high = mid - 1;
        }
        else if (arr[mid] < target)
        {
            low = mid + 1;
        }
    }
    return -1;
}