用C语言编写程序实现顺序查找和折半查找

以下是C语言实现顺序查找和折半查找的示例代码：

### 顺序查找

#include <stdio.h>

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

int main() {
    int arr[] = {2, 4, 7, 8, 10, 12};
    int n = sizeof(arr) / sizeof(arr[0]);
    int x = 8;
    int index = seq_search(arr, n, x);
    if (index == -1) {
        printf("%d not found", x);
    } else {
        printf("%d found at index %d", x, index);
    }
    return 0;
}

### 折半查找

#include <stdio.h>

int binary_search(int arr[], int low, int high, int x) {
    while (low <= high) {
        int mid = (low + high) / 2;
        if (arr[mid] == x) {
            return mid;
        } else if (arr[mid] < x) {
            low = mid + 1;
        } else {
            high = mid - 1;
        }
    }
    return -1;
}

int main() {
    int arr[] = {2, 4, 7, 8, 10, 12};
    int n = sizeof(arr) / sizeof(arr[0]);
    int x = 8;
    int index = binary_search(arr, 0, n-1, x);
    if (index == -1) {
        printf("%d not found", x);
    } else {
        printf("%d found at index %d", x, index);
    }
    return 0;
}