c语言完成顺序查找与折半查找代码实现

顺序查找代码实现：

#include <stdio.h>

int seq_search(int arr[], int n, int x)
{
    for (int i = 0; i < n; i++) {
        if (arr[i] == x) {
            return i;
        }
    }
    return -1;
}

int main()
{
    int arr[] = {3, 5, 7, 9, 11, 13, 15};
    int n = sizeof(arr) / sizeof(arr[0]);
    int x = 9;
    int idx = seq_search(arr, n, x);
    if (idx != -1) {
        printf("%d is at index %d\n", x, idx);
    } else {
        printf("%d is not found\n", x);
    }
    return 0;
}

折半查找代码实现：

#include <stdio.h>

int binary_search(int arr[], int n, int x)
{
    int l = 0;
    int r = n - 1;
    while (l <= r) {
        int m = (l + r) / 2;
        if (arr[m] == x) {
            return m;
        } else if (arr[m] < x) {
            l = m + 1;
        } else {
            r = m - 1;
        }
    }
    return -1;
}

int main()
{
    int arr[] = {3, 5, 7, 9, 11, 13, 15};
    int n = sizeof(arr) / sizeof(arr[0]);
    int x = 9;
    int idx = binary_search(arr, n, x);
    if (idx != -1) {
        printf("%d is at index %d\n", x, idx);
    } else {
        printf("%d is not found\n", x);
    }
    return 0;
}