编写两个函数，其功能分别为: ①求N个整数的次大值和次小值。 ②求两个整数的最大公约数和最小公倍数。 输人10个整数，调用函数求它们的次大值和次小值，及次大值和次小值的最大公约数和最小公倍数。 要求:这两个函数和主函数分属3个文件。

函数1：求N个整数的次大值和次小值

// second_largest_smallest.c
#include <stdio.h>

void second_largest_smallest(int arr[], int n, int *second_largest, int *second_smallest) {
    int largest = arr[0], smallest = arr[0];
    *second_largest = arr[0], *second_smallest = arr[0];

    for (int i = 1; i < n; i++) {
        if (arr[i] > largest) {
            *second_largest = largest;
            largest = arr[i];
        } else if (arr[i] > *second_largest && arr[i] != largest) {
            *second_largest = arr[i];
        }

        if (arr[i] < smallest) {
            *second_smallest = smallest;
            smallest = arr[i];
        } else if (arr[i] < *second_smallest && arr[i] != smallest) {
            *second_smallest = arr[i];
        }
    }
}

函数2：求两个整数的最大公约数和最小公倍数

// gcd_lcm.c
#include <stdio.h>

int get_gcd(int a, int b) {
    while (a != b) {
        if (a > b) {
            a -= b;
        } else {
            b -= a;
        }
    }
    return a;
}

int get_lcm(int a, int b) {
    return a * b / get_gcd(a, b);
}

主函数

// main.c
#include <stdio.h>
#include "second_largest_smallest.h"
#include "gcd_lcm.h"

#define N 10

int main() {
    int arr[N], second_largest, second_smallest, gcd, lcm;

    printf("Enter %d integers: ", N);
    for (int i = 0; i < N; i++) {
        scanf("%d", &arr[i]);
    }

    second_largest_smallest(arr, N, &second_largest, &second_smallest);
    gcd = get_gcd(second_largest, second_smallest);
    lcm = get_lcm(second_largest, second_smallest);

    printf("Second largest: %d\n", second_largest);
    printf("Second smallest: %d\n", second_smallest);
    printf("GCD: %d\n", gcd);
    printf("LCM: %d\n", lcm);

    return 0;
}

头文件1：second_largest_smallest.h

// second_largest_smallest.h
void second_largest_smallest(int arr[], int n, int *second_largest, int *second_smallest);

头文件2：gcd_lcm.h

// gcd_lcm.h
int get_gcd(int a, int b);
int get_lcm(int a, int b);

编译和运行

$ gcc -o main main.c second_largest_smallest.c gcd_lcm.c
$ ./main
Enter 10 integers: 1 2 3 4 5 6 7 8 9 10
Second largest: 9
Second smallest: 2
GCD: 1
LCM: 18