recursion-bin.c

    /*
     * C Program to Perform Binary Search using Recursion
     */
    #include <stdio.h>
     
    void binary_search(int [], int, int, int);
    void bubble_sort(int [], int);
     
    int main()
    {
        int key, size, i;
        int list[25];
     
        printf("Enter size of a list: ");
        scanf("%d", &size);
        printf("Generating random numbers\n");
        for(i = 0; i < size; i++)
        {
            list[i] = rand() % 100;
            printf("%d  ", list[i]);
        }
        bubble_sort(list, size);
        printf("\n\n");
        printf("Enter key to search\n");
        scanf("%d", &key);
        binary_search(list, 0, size, key);
     
    }
     
    void bubble_sort(int list[], int size)
    {
        int temp, i, j;
        for (i = 0; i < size; i++)
        {
            for (j = i; j < size; j++)
            {
                if (list[i] > list[j])
                {
                    temp = list[i];
                    list[i] = list[j];
                    list[j] = temp;
                }
            }
        }
    }
     
    void binary_search(int list[], int lo, int hi, int key)
    {
        int mid;
     
        if (lo > hi)
        {
            printf("Key not found\n");
            return;
        }
        mid = (lo + hi) / 2;
        if (list[mid] == key)
        {
            printf("Key found\n");
        }
        else if (list[mid] > key)
        {
            binary_search(list, lo, mid - 1, key);
        }
        else if (list[mid] < key)
        {
            binary_search(list, mid + 1, hi, key);
        }
    }