Searching in C-language

 1#include<stdio.h>
 2int lsearch(int b[],int n,int key);
 3void main()
 4{
 5    int a[20],num,k,loc,i;
 6    printf("\nEnter the number of elements in the list:");
 7    scanf("%d",&num);
 8    printf("Enter the elements of the list:\n");
 9    for(i=0;i<num;i++)
10    scanf("%d",&a[i]);
11    printf("Enter the key you are searching for:\n");
12    scanf("%d",&k);
13    loc = lsearch(a,num,k);
14    if(loc!=-1)
15    printf("successful search %d is found at %d\n",k,loc+1);
16    else{
17        printf("unsuccessful search\n");
18    }
19
20}
21int lsearch(int b[],int n,int key)
22{
23    int i;
24    for(i=0;i<n;i++)
25    {
26        if(b[i]==key)
27        return i;
28    }
29    return -1;
30}

 1#include <stdio.h>
 2int bsearch(int a[], int n, int key);
 3void main()
 4{
 5    int a[20], n, i, k, pos = -1;
 6    printf("Enter the number of elements in the given array:\n");
 7    scanf("%d", &n);
 8    printf("Enter the elements of an array:\n");
 9    for (i = 0; i < n; i++)
10    {
11        scanf("%d", &a[i]);
12    }
13    printf("Enter the key you are searching for:\n");
14    scanf("%d", &k);
15    pos = bsearch(a, n, k);
16    if (pos != -1)
17    {
18        printf("the key %d is found at %d", k, pos + 1);
19    }
20    else
21        printf("the key is not found\n");
22}
23int bsearch(int a[], int n, int key)
24{
25    int first = 0, last = n - 1, middle;
26    while (first <= last)
27    {
28        middle = (first + last) / 2;
29        if (key < a[middle])
30            last = middle - 1;
31        else if (key > a[middle])
32            first = middle + 1;
33        else
34            return middle;
35    }
36}