以上程序不使用stdib.h

好的，以下是不依赖于 `stdlib.h` 的实现：

#include <stdio.h>
#include <string.h>

#define MAX_LEN 20
#define MAX_NUM 10

// 定义日期结构体
typedef struct {
    int year;
    int month;
    int day;
} Date;

// 定义联系人结构体
typedef struct {
    char name[MAX_LEN];
    Date birthday;
    char phone[MAX_LEN];
} Person;

// 比较函数，按年龄从大到小排序
int cmp(Person a, Person b) {
    if (a.birthday.year != b.birthday.year) {
        return b.birthday.year - a.birthday.year;
    } else if (a.birthday.month != b.birthday.month) {
        return b.birthday.month - a.birthday.month;
    } else {
        return b.birthday.day - a.birthday.day;
    }
}

// 冒泡排序
void bubble_sort(Person people[], int n) {
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n - i - 1; j++) {
            if (cmp(people[j], people[j + 1]) > 0) {
                Person temp = people[j];
                people[j] = people[j + 1];
                people[j + 1] = temp;
            }
        }
    }
}

int main() {
    int n;
    Person people[MAX_NUM];
    printf("请输入联系人数量（不超过10个）：");
    scanf("%d", &n);

    if (n <= 0 || n > MAX_NUM) {
        printf("输入错误！\n");
        return 0;
    }

    printf("请分别输入联系人的姓名、生日（年 月 日）、电话号码：\n");
    for (int i = 0; i < n; i++) {
        scanf("%s %d %d %d %s", people[i].name, &people[i].birthday.year, &people[i].birthday.month, &people[i].birthday.day, people[i].phone);
    }

    // 排序
    bubble_sort(people, n);

    // 输出
    for (int i = 0; i < n; i++) {
        printf("%s %04d%02d%02d %s\n", people[i].name, people[i].birthday.year, people[i].birthday.month, people[i].birthday.day, people[i].phone);
    }

    return 0;
}

这里使用了冒泡排序进行排序。冒泡排序是比较简单的一种排序算法，虽然时间复杂度较高，但对于数据规模较小的情况，其性能表现不错。