binary_search.c

#include <stdio.h>
void isort(int *arr , int n){
        int i = 1,
            pos = 0,
            v = 0;
        while(i < n){
                v = arr[i];
                pos = i;
                while(pos > 0 && arr[pos-1] > v){
                        arr[pos] = arr[pos-1];
                        --pos;
                }
                arr[pos] = v;
                ++i;
        }
}
int binary_search(int *arr , int el , int left , int right){
        if(left > right)
                return -1;
        int mid = (left + right)/2;
        if(arr[mid] == el){
                return mid;
        }else if(arr[mid] > el){
                return binary_search(arr,el,left , mid-1);
        }
        return binary_search(arr,el,mid+1,right);
}
void main(){
        int a[100];
        int i,n = 0;
        int pos = 0;
        int el = 0;

        printf("Enter the upper limit: ");
        scanf("%d" , &n);
        for(i=0;i<n;++i){
                printf("Enter value[%d]: " , i+1);
                scanf("%d" , a + i);
        }
        isort(a , n);
        printf("Sorted Array: ");
        for(i=0;i<n-1;++i){
                printf(" [%d]( %d ) , " , i+1 , a[i]);
        }
        printf(" [%d]( %d ) .\n\n" , i+1 , a[i]);
        printf("Enter element to search: ");
        scanf("%d" , &el);
        if((pos = binary_search(a , el , 0 , n)) < 0){
                printf("Element not found in the array.\n");
                return;
        }
        printf("Element found at position %d.\n" , pos+1);
}