6

4

#include <stdio.h>
#define N 10

typedef struct {
    char isbn[20];          // isbn号
    char name[80];          // 书名
    char author[80];        // 作者
    double sales_price;     // 售价
    int  sales_count;       // 销售册数
} Book;

void output(Book x[], int n);
void sort(Book x[], int n);
double sales_amount(Book x[], int n);

int main() {
     Book x[N] = {{"978-7-5327-6082-4", "门将之死", "罗纳德.伦", 42, 51},
                  {"978-7-308-17047-5", "自由与爱之地：入以色列记", "云也退", 49 , 30},
                  {"978-7-5404-9344-8", "伦敦人", "克莱格泰勒", 68, 27},
                  {"978-7-5447-5246-6", "软件体的生命周期", "特德姜", 35, 90}, 
                  {"978-7-5722-5475-8", "芯片简史", "汪波", 74.9, 49},
                  {"978-7-5133-5750-0", "主机战争", "布莱克.J.哈里斯", 128, 42},
                  {"978-7-2011-4617-1", "世界尽头的咖啡馆", "约翰·史崔勒基", 22.5, 44},
                  {"978-7-5133-5109-6", "你好外星人", "英国未来出版集团", 118, 42},
                  {"978-7-1155-0509-5", "无穷的开始:世界进步的本源", "戴维·多伊奇", 37.5, 55},
                  {"978-7-229-14156-1", "源泉", "安.兰德", 84, 59}};
    
    printf("图书销量排名(按销售册数): \n");
    sort(x, N);
    output(x, N);

    printf("\n图书销售总额: %.2f\n", sales_amount(x, N));
    
    return 0;
}





void sort(Book x[], int n){
int i,j;
Book temp; 
for(i = 0;i < n-1;i++){
    for(j = 0;j < n-1-i;j++){
        if(x[j].sales_count < x[j+1].sales_count){
            temp = x[j];
            x[j] = x[j+1];
            x[j+1] = temp;
        }
    }
}
}

double sales_amount(Book x[], int n){
int i;
double sum = 0.0;
for(i = 0;i < n;i++){
    sum += x[i].sales_count*x[i].sales_price;
}
    return sum;
}


void output(Book x[], int n){
int i;
double sum;
printf("ISBN号              书名                                作者                 售价    销售册数\n");
for(i = 0;i < n;i++){
    printf("%s   %-35s %-20s %g       %d",x[i].isbn,x[i].name,x[i].author,x[i].sales_price,x[i].sales_count);    
    printf("\n");
}
    
}

5

#include <stdio.h>

typedef struct {
    int year;
    int month;
    int day;
} Date;

// 函数声明
void input(Date *pd);                   // 输入日期给pd指向的Date变量
int day_of_year(Date d);                // 返回日期d是这一年的第多少天
int compare_dates(Date d1, Date d2);    // 比较两个日期: 
                                        // 如果d1在d2之前，返回-1;
                                        // 如果d1在d2之后，返回1
                                        // 如果d1和d2相同，返回0

void test1() {
    Date d;
    int i;

    printf("输入日期:(以形如2025-12-19这样的形式输入)\n");
    for(i = 0; i < 3; ++i) {
        input(&d);
        printf("%d-%02d-%02d是这一年中第%d天\n\n", d.year, d.month, d.day, day_of_year(d));
    }
}

void test2() {
    Date Alice_birth, Bob_birth;
    int i;
    int ans;

    printf("输入Alice和Bob出生日期:(以形如2025-12-19这样的形式输入)\n");
    for(i = 0; i < 3; ++i) {
        input(&Alice_birth);
        input(&Bob_birth);
        ans = compare_dates(Alice_birth, Bob_birth);
        
        if(ans == 0)
            printf("Alice和Bob一样大\n\n");
        else if(ans == -1)
            printf("Alice比Bob大\n\n");
        else
            printf("Alice比Bob小\n\n");
    }
}

int main() {
    printf("测试1: 输入日期, 打印输出这是一年中第多少天\n");
    test1();

    printf("\n测试2: 两个人年龄大小关系\n");
    test2();
}

// 补足函数input实现
// 功能: 输入日期给pd指向的Date变量
void input(Date *pd) {
    scanf("%d-%d-%d",&pd->year ,&pd->month ,&pd->day );
}

// 补足函数day_of_year实现
// 功能：返回日期d是这一年的第多少天
int day_of_year(Date d) {
    int sum = 0;
    sum += d.day;
    if(d.month == 1) return sum;
    if(d.month == 2){
        sum += 31;
        return sum;
    }
    if(d.year % 400 == 0 || (d.year % 4 == 0 && d.year % 100 != 0)){
        if(d.month == 3){
            sum += 31 + 29;
            return sum;
        } 
        if(d.month == 4){
            sum += 31+29+31;
            return sum;
        }
        if(d.month == 5){
            sum += 31+29+31+30;
            return sum;
        }
        if(d.month == 6){
            sum += 31+29+31+30+31;
            return sum;
        }
        if(d.month == 7){
            sum += 31+29+31+30+31+30;
            return sum;
        }
        if(d.month == 8){
            sum += 31+29+31+30+31+30+31;
            return sum;
        }
        if(d.month == 9){
            sum += 31+29+31+30+31+30+31+31;
            return sum;
        }
        if(d.month == 10){
            sum += 31+29+31+30+31+30+31+31+30;
            return sum;
        }
        if(d.month == 11){
            sum += 31+29+31+30+31+30+31+31+30+31;
            return sum;
        }
        if(d.month == 12){
            sum += 31+29+31+30+31+30+31+31+30+31+30;
            return sum;
        }
    }
        if(!(d.year % 400 == 0 || (d.year % 4 == 0 && d.year % 100 != 0))){
        if(d.month == 3){
            sum += 31 + 28;
            return sum;
        } 
        if(d.month == 4){
            sum += 31+28+31;
            return sum;
        }
        if(d.month == 5){
            sum += 31+28+31+30;
            return sum;
        }
        if(d.month == 6){
            sum += 31+28+31+30+31;
            return sum;
        }
        if(d.month == 7){
            sum += 31+28+31+30+31+30;
            return sum;
        }
        if(d.month == 8){
            sum += 31+28+31+30+31+30+31;
            return sum;
        }
        if(d.month == 9){
            sum += 31+28+31+30+31+30+31+31;
            return sum;
        }
        if(d.month == 10){
            sum += 31+28+31+30+31+30+31+31+30;
            return sum;
        }
        if(d.month == 11){
            sum += 31+28+31+30+31+30+31+31+30+31;
            return sum;
        }
        if(d.month == 12){
            sum += 31+28+31+30+31+30+31+31+30+31+30;
            return sum;
        }
}
}

// 补足函数compare_dates实现
// 功能：比较两个日期: 
// 如果d1在d2之前，返回-1;
// 如果d1在d2之后，返回1
// 如果d1和d2相同，返回0
int compare_dates(Date d1, Date d2) {
    if(d1.year > d2.year ) return 1;
    if(d1.year < d2.year ) return -1;
    if(d1.year == d2.year ){
        if(day_of_year(d1) == day_of_year(d2)) return 0;
        if(day_of_year(d1) > day_of_year(d2)) return 1;
        if(day_of_year(d1) < day_of_year(d2)) return -1;
    }
}

6

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

enum Role {admin, student, teacher};

typedef struct {
    char username[20];  // 用户名
    char password[20];  // 密码
    enum Role type;     // 账户类型
} Account;


// 函数声明
void output(Account x[], int n);    // 输出账户数组x中n个账户信息，其中，密码用*替代显示

int main() {
    Account x[] = {{"A1001", "123456", student},
                    {"A1002", "123abcdef", student},
                    {"A1009", "xyz12121", student}, 
                    {"X1009", "9213071x", admin},
                    {"C11553", "129dfg32k", teacher},
                    {"X3005", "921kfmg917", student}};
    int n;
    n = sizeof(x)/sizeof(Account);
    output(x, n);

    return 0;
}

// 待补足的函数output()实现
// 功能：遍历输出账户数组x中n个账户信息
//      显示时，密码字段以与原密码相同字段长度的*替代显示
void output(Account x[], int n) {
    int i,j,len;
    for(i = 0;i < n;i++){
        len = strlen(x[i].password);
        printf("%-20s",x[i].username);
        for(j = 0;j < len;j++){
            printf("*");
        }
        printf("\t\t");
        switch(x[i].type){
            case admin: printf("admin");break;
            case student: printf("student");break;
            case teacher: printf("teacher");break;
        }
        printf("\n");
    }
}

7

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

typedef struct {
    char name[20];      // 姓名
    char phone[12];     // 手机号
    int  vip;           // 是否为紧急联系人，是取1；否则取0
} Contact; 


// 函数声明
void set_vip_contact(Contact x[], int n, char name[]);  // 设置紧急联系人
void output(Contact x[], int n);    // 输出x中联系人信息
void display(Contact x[], int n);   // 按联系人姓名字典序升序显示信息，紧急联系人最先显示


int compare_contacts(const void *a, const void *b)
 {
    Contact *ca = (Contact *)a;
    Contact *cb = (Contact *)b;
    
    if(ca->vip != cb->vip) {
        return cb->vip - ca->vip;  
    }
    
    
    return strcmp(ca->name, cb->name);
}


#define N 10
int main() {
    Contact list[N] = {{"刘一", "15510846604", 0},
                       {"陈二", "18038747351", 0},
                       {"张三", "18853253914", 0},
                       {"李四", "13230584477", 0},
                       {"王五", "15547571923", 0},
                       {"赵六", "18856659351", 0},
                       {"周七", "17705843215", 0},
                       {"孙八", "15552933732", 0},
                       {"吴九", "18077702405", 0},
                       {"郑十", "18820725036", 0}};
    int vip_cnt, i;
    char name[20];

    printf("显示原始通讯录信息: \n"); 
    output(list, N);

    printf("\n输入要设置的紧急联系人个数: ");
    scanf("%d", &vip_cnt);
    
    printf("输入%d个紧急联系人姓名:\n", vip_cnt);
    for(i = 0; i < vip_cnt; ++i) {
        scanf("%s", name);
        set_vip_contact(list, N, name);
    }

    printf("\n显示通讯录列表:(按姓名字典序升序排列,紧急联系人最先显示)\n");
    display(list, N);

    return 0;
}

// 补足函数set_vip_contact实现
// 功能：将联系人数组x中，联系人姓名与name一样的人，设置为紧急联系人（即成员vip值设为1）
void set_vip_contact(Contact x[], int n, char name[]) {
     int i;
     for(i = 0;i < n;i++){
         if(!(strcmp(name,x[i].name))){
             x[i].vip = 1;
         }
     }
}

// 补足函数display实现
// 功能: 显示联系人数组x中的联系人信息
//      按姓名字典序升序显示, 紧急联系人显示在最前面
void display(Contact x[], int n) {
    int i,j=0;
    Contact temp[n];
     for(i = 0;i < n;i++){
        if(x[i].vip){
            printf("%-10s%-15s", x[i].name, x[i].phone);
            printf("%5s","*");
            printf("\n");
        }
     }
     for(i = 0;i < n;i++){
         if(!(x[i].vip)){
         strcpy(temp[j].name, x[i].name);
        strcpy(temp[j].phone, x[i].phone);
        temp[j].vip = x[i].vip;
        j++;
         }
     }
     qsort(temp, j, sizeof(Contact),compare_contacts);
     
     for(i = 0;i < j;i++){
             printf("%-10s%-15s", temp[i].name, temp[i].phone);
            printf("\n");
     }
}

void output(Contact x[], int n) {
    int i;

    for(i = 0; i < n; ++i) {
        printf("%-10s%-15s", x[i].name, x[i].phone);
        if(x[i].vip)
            printf("%5s", "*");
        printf("\n");
    }
}

8