C primer plus第14章(结构和其他数据形式)（练习）

//练习3、4、5#include <stdio.h>struct month{    char name[10];    char nik[4];    int days;    int month;};struct month months[12] ={    {"January","jan",31,1},    {"February","feb",28,2},    {"March","mar",31,3},    {"April","apr",30,4},    {"May","may",31,5},    {"June","jun",30,6},    {"July","jul",31,7},    {"August","aug",31,8},    {"September","sep",30,9},    {"October","oct",31,10},    {"November","nov",30,11},    {"December","dec",31,12}};int getDays(int month){    int i;    int totaldays = 0;    extern struct month months[];    for(i=1; i<month; i++)    {        totaldays += months[i].days;    }    return totaldays;}int main(void){    printf("%d",getDays(2));    return 0;}

//练习6

#include <stdio.h>#include <string.h>typedef struct lens  //镜头描述{    float foclen;   //焦距长度，以mm为单位    float fstop;    //孔径    char brand[30]; //品牌名称} LENS;int main(void){    //a赋值    LENS l[10];    l[2].foclen = 500;    l[2].fstop = 2.0;    //字符串如不赋值拷贝的只是地址    strcpy(l[2].brand,"Remarkatar");    //b直接初始化第三个下标的元素    LENS bigEye[10] = {[2] = {500,2,"Remarkatar"}};    return 0;}

练习7

#include <stdio.h>struct name{    char first[20];    char last[20];};struct bem{    int limbs;    struct name title;    char type[30];};int main(void){    struct bem *pb;    struct bem deb =    {        6,        {"Berbanazel","Gwolkapwolk"},        "Arcturan"    };    pb = &deb;    printf("%d\n",deb.limbs);    printf("%s\n",pb->type);    printf("%s\n",pb->type+2);    return 0;}

打印结果
6
Arcturan
cturan

b使用结构鸣并使用指针

deb.title.last

pb->title.last

c

void show(const struct bem *pb){    printf("%s %s is a %d-limbed %s.",pb->title.first,pb->title.last,pb->limbs,pb->type);}

8

#include <stdio.h>struct fullname{    char fname[20];    char lname[20];};struct bard{    struct fullname name;    int born;    int died;};int main(void){    struct bard willie;    struct bard *pt = &willie;    //a    willie.born;    //b    pt->born;    //c    scanf("%d",willie.born);    //d    scanf("%d",pt->born);    //e    scanf("%d",willie.name.lname);    //f    scanf("%d",pt->name.lname);    //g    willie.name.fname[2];    //h    strlen(willie.name.fname) + strlen(willie.name.lname);    return 0;}

9

struct car{    char name[100];//车名    int horseprower;//马力    int epa;//epa英里每加仑（mpg）等级    float wheelBase; //轴距    int years;//使用年限};

10

struct gas{    float distance;    float gals;    float mpg;};//astruct gas cal(struct gas g){    g.mpg = g.distance * g.gals;    return g;}//bvoid cal2(struct gas * g){    g->mpg = g->distance * g->gals;}

11

enum choices{    no,    yes,    maybe};

12 

char *(*pfun)(char *,char)

char *    返回值是个char指针

(*pfun) 是函数指针

(char *,char) 2个参数一个char指针，一个char

13

double a(double, double);
double b(double, double);
double c(double, double);
double d(double, double);


double (*abcd[4])(double,double) = {a,b,c,d};
//或者
typedef double (*abcd)(double,double);
abcd d[4] = {a,b,c,d};

编程练习

1.

//练习3、4、5#include <stdio.h>struct month{    char name[10];    char nik[4];    int days;    int month;};//枚举类型代替1-12的数字enum monthEnum{    January,    February,    March,    April,    May,    June,    July,    August,    September,    October,    November,    December};//月份用枚举标示struct month months[12] ={    {"January","jan",31,January},    {"February","feb",28,February},    {"March","mar",31,March},    {"April","apr",30,April},    {"May","may",31,May},    {"June","jun",30,June},    {"July","jul",31,July},    {"August","aug",31,August},    {"September","sep",30,September},    {"October","oct",31,October},    {"November","nov",30,November},    {"December","dec",31,December}};int getDays(int month){    int i;    int totaldays = 0;    extern struct month months[];    for(i=1; i<month; i++)    {        totaldays += months[i].days;    }    return totaldays;}int main(void){    printf("%d",getDays(2));    return 0;}

2

#include <stdio.h>#include <stdlib.h>#include <string.h>struct month{    char name[10];    char nik[4];    int days;    int month;};struct month months[12] ={    {"January","jan",31,1},    {"February","feb",28,2},    {"March","mar",31,3},    {"April","apr",30,4},    {"May","may",31,5},    {"June","jun",30,6},    {"July","jul",31,7},    {"August","aug",31,8},    {"September","sep",30,9},    {"October","oct",31,10},    {"November","nov",30,11},    {"December","dec",31,12}};int getDays(int year, const struct month *m,int day);int main(void){    size_t year,day,i;    char mon[20];    struct month *m = NULL;    printf("请输入年份:");    while(scanf("%d",&year) != 1)    {        printf("请输入一个正整数年份:");    }    //吃掉回城符    getchar();    printf("请输入月份:");    gets(mon);    while(m == NULL)    {        for(i=1; i<= 12; i++)        {            if(strcmp(months[i].name,mon) == 0 || strcmp(months[i].nik,mon) == 0 || months[i].month == atoi(mon))            {                m = &months[i];            }        }    }    printf("请输入日期:");    while(scanf("%d",&day) != 1)    {        printf("请输入一个正整数日期:");    }    printf("%d",getDays(year,m,day));    return 0;}//根据年月日获取天数int getDays(int year, const struct month *m,int day){    if(year< 0 || day <0 || day > m->days)    {        printf("year = %d, day=%d,m->day = %d",year,day,m->days);        return 0;    }    int totaldays = 0;    if(m->month == 2 && year%4 == 0 && year%100 !=0)    {        totaldays++;    }    int i;    for(i=0; i<m->month-1; i++)    {        totaldays += months[i].days;    }    totaldays += day;    return totaldays;}

3

#include <stdio.h>#define MAXTITL 40#define MAXAUTL 40#define MAXBKS 100 //图书最多的本书//建立book模板struct book{    char title[MAXTITL];    char author[MAXAUTL];    float value;};void titleSort(struct book library[],int count);void valueSort(struct book library[],int count);int main(void){    struct book library[MAXBKS];//结构数组    int count = 0;    int index;    //如果文件还能存储    puts("Please enter the book title.");    puts("Press [enter] at the start of a line to stop.");    //录入新的图书    while(count <MAXBKS && gets(library[count].title) != NULL && library[count].title[0] != '\0')    {        puts("Now enter the author.");        gets(library[count].author);        puts("Now enter the value.");        //下标递增        scanf("%f",&library[count++].value);        //清空输入行        while(getchar() != '\n')        {            continue;        }        //如果未大于最大存储数量，提示输入下一本        if(count< MAXBKS)        {            puts("Enter the next title");        }    }    if(count > 0)    {        puts("Here is the list of your books:");        for(index = 0; index < count; index++)        {            printf("%s by %s:$%.2f\n",library[index].title,library[index].author,library[index].value);        }        titleSort(library,count);        valueSort(library,count);    }    else    {        puts("No books? Too bad.\n");    }    return 0;}void titleSort(struct book library[],int count){    printf("\n按title首字母升序:\n");    int i,j,temp,flag;    int sort[count];    for(i=0; i<count; i++)    {        sort[i] = i;    }    //选择排序    for(i=0; i<count-1; i++)    {        temp = sort[i];        flag = i;        for(j=i+1; j<count; j++)        {            if(library[temp].title[0] > library[sort[j]].title[0])            {                temp = sort[j];                flag = j;            }            if(flag != i)            {                sort[flag] = sort[i];                sort[i] = temp;            }        }    }    for(i=0; i<count; i++)    {        printf("%s by %s:$%.2f\n",library[sort[i]].title,library[sort[i]].author,library[sort[i]].value);    }}void valueSort(struct book library[],int count){    printf("\n按value升序:\n");    int i,j,temp,flag;    int sort[count];    for(i=0; i<count; i++)    {        sort[i] = i;    }    //选择排序    for(i=0; i<count-1; i++)    {        flag = i;        for(j=i+1; j<count; j++)        {            if(library[sort[flag]].value>library[sort[j]].value)            {                flag = j;            }            if(flag != i)            {                temp = sort[i];                sort[i] = sort[j];                sort[j] = temp;            }        }    }    for(i=0; i<count; i++)    {        printf("%s by %s:$%.2f\n",library[sort[i]].title,library[sort[i]].author,library[sort[i]].value);    }}

4

#include <stdio.h>#include <string.h>//建立book模板struct name{    char firstName[20];    char middleName[20];    char lastName[20];};struct citizen{    int socialSecurityNO;    struct name citizenName;};void printA(const struct citizen country);void printB(const struct citizen *country);int main(void){    int i;    struct citizen country[5] =    {        {10000001,{"h1","x1","l"}},        {10000002,{"h2","","l"}},        {10000003,{"h3","x3","l"}},        {10000004,{"h4","x4","l"}},        {10000005,{"h5","x5","l"}}    };    for(i=0; i<5; i++)    {        //printA(country[i]);        printB(&country[i]);    }    return 0;}void printA(const struct citizen country){    printf("%s.%s ",country.citizenName.firstName,country.citizenName.lastName);    if(strlen(country.citizenName.middleName) > 0)    {        printf("%c.",country.citizenName.middleName[0]);    }    printf("-%d\n",country.socialSecurityNO);}void printB(const struct citizen *country){    printf("%s.%s ",country->citizenName.firstName,country->citizenName.lastName);    if(strlen(country->citizenName.middleName) > 0)    {        printf("%c.",country->citizenName.middleName[0]);    }    printf("-%d\n",country->socialSecurityNO);}

5

#include <stdio.h>#define CSIZE 4//建立book模板struct name{    char firstName[20];    char lastName[20];};struct student{    struct name sname;    //分数    float grade[3];    //平均分    double avgGrade;};void getStudent(struct student *s);void putStudents(struct student students[]);int main(void){    struct student students[CSIZE];    int i;    for(i=0; i<CSIZE; i++)    {        printf("第%d名学生\n",i+1);        getStudent(&students[i]);    }    putStudents(students);    return 0;}void getStudent(struct student *s){    puts("请输入姓");    gets(s->sname.firstName);    puts("请输入名");    gets(s->sname.lastName);    int i;    double total = 0;    for(i=0; i<3; i++)    {        printf("请输第%d门分数",i+1);        scanf("%f",&s->grade[i]);        getchar();        total += s->grade[i];    }    s->avgGrade = total/3;}void putStudents(struct student students[]){    int i,j;    double total = 0;    for(i =0; i<CSIZE; i++)    {        printf("学生%s.%s\n",students[i].sname.firstName,students[i].sname.lastName);        for(j=0; j<3; j++)        {            printf("成绩%d:%f\n",j+1,students[i].grade[j]);        }        total += students[i].avgGrade;    }    printf("班级平均成绩%lf",total/CSIZE);}

6（未完成）

//练习3、4、5#include <stdio.h>#include <stdlib.h>#define LEN 20#define MAX 100//棒球选手typedef struct ballplayer{    //球员编号    size_t no;    char lastname[LEN];    char firstname[LEN];    //上场击球次数    int timesAtBat;    //击中数    int timesAtHit;    //跑垒数    int timesAtBaseRunning;    //跑点数    int RBI;    //平均成功率    double averageSuccessRatio;} BP;int getInt();void getBallPalyer(BP *bp);int main(void){    BP team[MAX];    int size = sizeof(BP);    FILE *fp;    int index = 0;    if((fp = fopen("team.txt","r")) == NULL)    {        puts("文件打开失败");        exit(EXIT_FAILURE);    }    while(fread(&team[index++],size,1,fp) == 1)    {        printf("%d %s.%s %d %d %d %d %d",team[index].no,team[index].firstname,team[index].lastname,team[index].timesAtBat,team[index].timesAtHit,team[index].timesAtBaseRunning,team[index].RBI,team[index].averageSuccessRatio);    }    return 0;}void getBallPalyer(BP *bp){    puts("请录入球员编号！");    bp->no = getInt();    puts("请输入球员姓:");    gets(bp->firstname);    puts("请输入球员名:");    gets(bp->lastname);    puts("请输入上场击球次数");    //上场击球次数    bp->timesAtBat = getInt();    //击中数    bp->timesAtHit = getInt();    //跑垒数    bp->timesAtBaseRunning = getInt();    //跑点数    bp->RBI = getInt();    //平均成功率    bp->averageSuccessRatio = bp->timesAtHit / bp->timesAtBat;}//获取int型的输入参数int getInt(){    int num;    while(scanf("%d",&num) != 1)    {        while(getchar() != '\n')        {            continue;        }        puts("请输入数字类型的编号");    }    return num;}

7

#include <stdio.h>#include <stdlib.h>#include <string.h>#define MAXTITL 40#define MAXAUTL 40#define MAXBKS 10 //图书最多的本书#define CONTINUE 0#define DONE 1#define YES 1#define NO 0//建立book模板struct book{    char title[MAXTITL];    char author[MAXAUTL];    float value;    //记录删除状态    int del;};int getlet(const char *s);int getbook(struct book *pb);void update(struct book * item);int main(void){    struct book library[MAXBKS];//结构数组    int count = 0;    int deleted = 0;//记录删除的数量    int index,filecount,open;    FILE *pbooks;    int size = sizeof(struct book);    //以读取模式打开文件流    if((pbooks = fopen("book.dat","r")) != NULL)    {        //读取并输出文件中已经存在的数据        while(count < MAXBKS && fread(&library[count],size,1,pbooks) == 1)        {            //读取第一条数据时显示标题            if(count == 0)            {                puts("Current contents of book.dat");            }            printf("%s by %s:$%.2f\n",library[count].title,library[count].author,library[count].value);            printf("Do you wish to change or delete this entry?<y/n>");            //获取输入            if(getlet("yn") == 'y')            {                printf("Enter c to change,d to delete entry:");                //获取输入                if(getlet("cd") == 'd')                {                    //删除标记                    library[count].del = YES;                    //删除数量增加                    deleted++;                    puts("Entry marked for deletion.");                }                else                {                    //更新数据                    update(&library[count]);                }            }            count++;        }        fclose(pbooks);    }    //计算记录数量 记录总数-删除的数据    filecount = count - deleted;    //如果文件存储已满    if(count == MAXBKS)    {        fputs("The book.dat file is full.",stderr);        exit(2);    }    //如果文件还能存储    puts("Please add new book titles.");    puts("Press [enter] at the start of a line to stop.");    open = 0;    while(filecount < MAXBKS)    {        if(filecount < count)        {            //统计所有没有删除的书            while(library[open].del == NO)            {                //此变量唯一用途是为后面新增书查询下标                open++;            }            //录入新的图书            if(getbook(&library[open]) == DONE)            {                break;            }        }        else if(getbook(&library[filecount]) == DONE)        {            //如果没有删除的书            break;        }        //继续统计新增后的书总量（扣除删除的）        filecount++;        if(filecount < MAXBKS)        {            puts("Enter the next book title.");        }    }    puts("Here is the list of your books:");    for(index = 0; index<filecount; index++)    {        if(library[index].del == NO)        {            printf("%s by %s: $%.2f\n",library[index].title,library[index].author,library[index].value);        }    }    //以写入（清空文件内容）的方式打开文件流    if((pbooks = fopen("book.dat","w")) == NULL)    {        fputs("Can`t open book.dat file for output\n",stderr);        exit(1);    }    //写入文件    for(index = 0; index<filecount; index++)    {        //删除的数据不写入        if(library[index].del == NO)        {            fwrite(&library[index],size,1,pbooks);        }    }    //关闭文件流    fclose(pbooks);    puts("Done!");    return 0;}//参数传入一个字符串，获取输入，字符串中的一个字符int getlet(const char * s){    char c;    c = getchar();    //功能：查找字符串s中首次出现字符c的位置    //说明：返回首次出现c的位置的指针，如果s中不存在c则返回NULL。    while(strchr(s,c) == NULL)    {        printf("Enter a character in the list %s\n",s);        //清空输入行 比如scanf()没有对'\n'做处理        while(getchar() != '\n')        {            continue;        }        //继续获取输入        c=getchar();    }    while(getchar() != '\n')    {        continue;    }    return c;}//录入新书int getbook(struct book * pb){    int status = CONTINUE;    if(gets(pb->title) == NULL || pb->title[0] == '\0')    {        status = DONE;//退出输出    }    else    {        printf("Now enter the auther:");        gets(pb->author);        printf("Now enter the value:");        while(scanf("%f",&pb->value) != 1)        {            puts("Please use numeric input");            scanf("%*s");        }        while(getchar() != '\n')        {            continue;//clear input line        }        pb->del = NO;    }    return status;}void update(struct book * item){    struct book copy;    char c;    copy = *item;    //修改菜单    puts("Enter the letter that indicates your choice:");    puts("t) modify title       a) modify author");    puts("v) modify value       s)quit,saving changes");    puts("q) quit,ignore changes");    while((c = getlet("tavsq")) != 's' && c != 'q')    {        switch(c)        {        case 't':            puts("Enter new title:");            gets(copy.title);            break;        case 'a':            puts("Enter new author:");            gets(copy.author);        case 'v':            puts("Enter new value:");            while(scanf("%f",©.value) != 1)            {                puts("Enter a numeric value:");                scanf("%*s");            }            while(getchar() != '\n')            {                continue;            }            break;        }        puts("t) modify title       a) modify author");        puts("v) modify value       s)quit,saving changes");        puts("q) quit,ignore changes");    }    if(c == 's')    {        *item = copy;    }}

8（丑陋，但是完成了）

#include <stdio.h>#include <stdlib.h>#include <stdbool.h>//bool头文件#include <string.h>#define LEN 12//座位席模板typedef struct planeSeat{    //座位号    char no;    //是否已预订    bool booked;    char firstName[LEN];    char lastName[LEN];} PSEAT;int getlet(const char *s);//读取文件void readFile(PSEAT *p,int size);//写入文件void writeFile(PSEAT *p,int size);//显示剩余座位数void showNumberOfEmptySeats(PSEAT *p);//显示剩余座位列表void showListOfEmptySeats(PSEAT *p);//按字母显示预订座位列表void showAlphabeticalListOfSeats(PSEAT *p);//预订座位void AssignACustomer(PSEAT *p);//删除预订void deleteACustomer(PSEAT *p);//显示菜单void menu(PSEAT *p);int main(void){    int size = sizeof(PSEAT);    PSEAT p[LEN];    readFile(p,size);    menu(p);    writeFile(p,size);    return 0;}void writeFile(PSEAT *p,int size){    int i;    FILE *fp = fopen("seatBook.dat","w");    for(i=0; i<LEN; i++)    {        fwrite((p+i),size,1,fp);    }}void readFile(PSEAT *p,int size){    FILE *fp;    int i;    if((fp = fopen("seatBook.dat","r")) != NULL)    {        for(i=0; i<LEN; i++)        {            fread((p+i),size,1,fp);        }        fclose(fp);    }    else    {        for(i=0; i<LEN; i++)        {            (p+i)->no = i;            (p+i)->booked = false;        }    }}//参数传入一个字符串，获取输入，字符串中的一个字符int getlet(const char * s){    char c;    c = getchar();    //功能：查找字符串s中首次出现字符c的位置    //说明：返回首次出现c的位置的指针，如果s中不存在c则返回NULL。    while(strchr(s,c) == NULL)    {        printf("Enter a character in the list %s\n",s);        //清空输入行 比如scanf()没有对'\n'做处理        while(getchar() != '\n')        {            continue;        }        //继续获取输入        c=getchar();    }    while(getchar() != '\n')    {        continue;    }    return c;}void showNumberOfEmptySeats(PSEAT *p){    int count = 0;    int i;    for(i=0; i<LEN; i++)    {        if((p+i)->booked == false)        {            count++;        }    }    printf("\n%d SEATS ARE not booked\n",count);}void showListOfEmptySeats(PSEAT *p){    int i;    for(i=0; i<LEN; i++)    {        if((p+i)->booked == false)        {            printf("NO.%d SEAT not booked\n",(p+i)->no);        }    }}void showAlphabeticalListOfSeats(PSEAT *p){    int sorts[LEN];    int i,j,flag,temp;    for(i=0; i<LEN; i++)    {        sorts[i] = i;    }    for(i = 0; i< LEN-1; i++)    {        flag = i;        for(j = i+1; j <LEN ; j++)        {            if((p+sorts[i])->firstName[0] > (p+sorts[j])->firstName[0])            {                flag = j;            }        }        if(flag != i)        {            temp = sorts[flag];            sorts[flag] = sorts[i];            sorts[i] = temp;        }    }    for(i=0; i<LEN; i++)    {        if((p+sorts[i])->booked == true)        {            printf("NO.%d SEAT is booked by %s.%s\n",(p+sorts[i])->no,(p+sorts[i])->firstName,(p+sorts[i])->lastName);        }    }}//预订座位void AssignACustomer(PSEAT *p){    int index;    puts("请输入要预订的座位号");    while(scanf("%d",&index) !=1 || index <0 || index > LEN)    {        while(getchar()!='\n')        {            continue;        }        puts("请输入0-12的数字");    }    while(getchar()!='\n')    {        continue;    }    puts("请输入姓");    gets((p+index)->firstName);    puts("请输入名字");    gets((p+index)->lastName);    (p+index)->booked = true;}void deleteACustomer(PSEAT *p){    int index;    puts("请输入要预订的座位号");    while(scanf("%d",&index) !=1 || index <0 || index > LEN)    {        while(getchar()!='\n')        {            continue;        }        puts("请输入0-12的数字");    }    while(getchar()!='\n')    {        continue;    }    //p[index]->firstName = "";    //p[index]->lastName = "";    (p+index-1)->booked = false;}void menu(PSEAT *p){    char ch;    puts("To choose a function,enter its letter label:");    puts("a)Show number of empty seats");    puts("b)Show list of empty seats");    puts("c)Show alphabetical list of seat");    puts("d)Assign a customer to a seat assignment");    puts("e)Delete a seat assignment");    puts("f)Quit");    while((ch = getlet("abcdef")) != 'f')    {        switch(ch)        {        case 'a':            showNumberOfEmptySeats(p);            break;        case 'b':            showListOfEmptySeats(p);            break;        case 'c':            showAlphabeticalListOfSeats(p);            break;        case 'd':            AssignACustomer(p);            break;        case 'e':            deleteACustomer(p);            break;        }    }}

8答案做法

#include <stdio.h>#include <stdlib.h>#include <stdbool.h>//bool头文件#include <string.h>#define LEN 14#define SEATS 12#define EMPTY 0#define TAKEN 1#define CONTINUE 1#define DONE 0struct planestats{    int seat_id;    int status;    char last[LEN];    char first[LEN];};int getmenu(void);int getlet(const char *);int openings(const struct planestats[],int);void show_empties(const struct planestats [],int);void list_assign(struct planestats *[],int);void assign_seat(struct planestats [],int);void delete_seat(struct planestats [],int);void show_seat(const struct planestats [],int);void sort(struct planestats *[],int);void makelist(const struct planestats [],char*,int);int main(void){    struct planestats plane_1[SEATS],*ps[SEATS];    int choice;    int i;    FILE *fp;    size_t size = sizeof(struct planestats);    for(i=0; i<SEATS; i++)    {        ps[i] = &plane_1[i];    }    if((fp = fopen("air.dat","rb")) == NULL)    {        for(i=0; i<SEATS; i++)        {            plane_1[i].status = EMPTY;            plane_1[i].seat_id = i+1;        }    }    else    {        fread(plane_1,size,SEATS,fp);        fclose(fp);    }    while((choice = getmenu()) != 'q')    {        switch(choice)        {        case 'o':            printf("There are %d empty seats.\n",openings(plane_1,SEATS));            break;        case 'e':            show_empties(plane_1,SEATS);            break;        case 'l':            list_assign(ps,SEATS);            break;        case 'a':            assign_seat(plane_1,SEATS);            break;        case 'd':            delete_seat(plane_1,SEATS);            break;        default:            puts("Switch trouble");            break;        }    }    if((fp = fopen("air.dat","wb")) == NULL)    {        puts("Can`t save data to file.");    }    else    {        fwrite(plane_1,size,SEATS,fp);        fclose(fp);    }    puts("Bye from Colossus Airlines!");    return 0;}#define CHOICES 6int getmenu(void){    const char *descript[CHOICES] =    {        "Show number of empty seats",        "Show list of empty seats",        "Show alphabetical list of seat assignments",        "Assign acustomer to a seat",        "Delete a seat assignment",        "Quit"    };    const char labels[CHOICES + 1] = "oeladq";    int i;    puts("To choose a function,enter its letter");    for(i =0; i<CHOICES; i++)    {        printf("%c) %s\n",labels[i],descript[i]);    }    return getlet(labels);}//参数传入一个字符串，获取输入，字符串中的一个字符int getlet(const char * s){    char c;    c = getchar();    //功能：查找字符串s中首次出现字符c的位置    //说明：返回首次出现c的位置的指针，如果s中不存在c则返回NULL。    while(strchr(s,c) == NULL)    {        printf("Enter a character in the list %s\n",s);        //清空输入行 比如scanf()没有对'\n'做处理        while(getchar() != '\n')        {            continue;        }        //继续获取输入        c=getchar();    }    while(getchar() != '\n')    {        continue;    }    return c;}int openings(const struct planestats pl[],int n){    int count = 0;    int seat;    for(seat = 0; seat < n; seat++)    {        if(pl[seat].status == EMPTY)        {            count++;        }    }    return count;}void show_empties(const struct planestats pl[],int n){    //int seat;    char seating[3*SEATS];    if(openings(pl,n) == 0)    {        puts("All seats are assigned");    }    else    {        puts("The following seats are avaliable:");        makelist(pl,seating,EMPTY);        puts(seating);    }}void makelist(const struct planestats pl[],char * str,int kind){    int seat;    char temp[LEN];    str[0] = '\0';    for (seat = 0; seat <SEATS; seat++)    {        if(pl[seat].status == kind)        {            sprintf(temp," %d",pl[seat].seat_id);            strcat(str,temp);        }    }}void list_assign(struct planestats *ps[],int n){    int i;    if(openings(*ps,n)==SEATS)    {        puts("All seats are empty.");    }    else    {        sort(ps,n);        for(i =0; i<SEATS; i++)        {            if(ps[i]->status == TAKEN)            {                printf("Seat %d: %s. %s\n",ps[i]->seat_id,ps[i]->last,ps[i]->first);            }        }    }}void assign_seat(struct planestats pl[],int n){    char list[3*SEATS];    int seat,loop;    if(openings(pl,n) == 0)    {        puts("All seats are assigned.");    }    else    {        makelist(pl,list,EMPTY);        puts("Which seat do you want? Choose from this list:");        puts(list);        do        {            while(scanf("%d",&seat) != 1)            {                scanf("%*s");                puts("Enter a number from this list:");                puts(list);            }            if(seat < 1 || seat > SEATS || pl[seat-1].status == TAKEN)            {                puts("Enter a number from this list:");                puts(list);                loop = CONTINUE;            }        }        while(loop == CONTINUE);        while(getchar() != '\n')        {            continue;        }        puts("Enter first name:");        gets(pl[seat -1].first);        puts("Enter last name:");        gets(pl[seat -1].last);        printf("%s %s assigned to seat %d.\n",pl[seat -1].first,pl[seat -1].last,seat);        puts("Enter a to accpt assignment, c to cancel it.");        if(getlet("ac") == 'a')        {            pl[seat - 1].status = TAKEN;            puts("Passenger assigned to seat.");        }        else        {            puts("Passenger not assigned.");        }    }}void show_seats(const struct planestats pl[],int n){    int i;    puts("Seats currently taken:");    for(i=0; i<SEATS; i++)    {        if(pl[i].status == TAKEN)        {            printf("Seat %d: %s, %s\n",pl[i].seat_id,pl[i].last,pl[i].first);        }    }}void delete_seat(struct planestats pl[],int n){    int seat,loop;    char list[3*SEATS];    if(openings(pl,n) == SEATS)    {        puts("All seats already are empty.");    }    else    {        show_seats(pl,n);        makelist(pl,list,TAKEN);        puts("Enter the number of the seat to be cancelled:");        do        {            while(scanf("%d",&seat) != 1)            {                scanf("%*s");                puts("Enter a number from this list:");                puts(list);            }            if(seat < 1 || seat > SEATS || pl[seat-1].status == EMPTY)            {                puts("Enter a number from this list;");                puts(list);                loop = CONTINUE;            }            else            {                loop = DONE;            }        }        while(loop == CONTINUE);        while(getchar() != '\n')        {            continue;        }        printf("%s %s to be canceled for seat %d.\n",pl[seat - 1].first,pl[seat - 1].last,seat);        puts("Enter d to delete assignment,a to abort.");        if(getlet("da") == 'd')        {            pl[seat -1].status = EMPTY;            puts("Passenger dropped.");        }        else        {            puts("Passenger retained.");        }    }}void sort(struct planestats *array[],int limit){    int top,search;    struct planestats * temp;    for(top = 0; top<limit-1; top++)    {        for(search = top +1; search <limit; search++)        {            if(strcmp(array[search]->last,array[top]->last)<0)            {                temp = array[search];                array[search] = array[top];                array[top] = temp;            }        }    }}

10

#include <stdio.h>#include <stdlib.h>void MyFunA(int x);void MyFunB(int x);void MyFunC(int x);void (*FunP)(int);typedef void(*FunType)(int);//定义一个函数指针类型的FunTYPEvoid CallMyFun(FunType fp,int x);int main(void){    size_t c;    while((c = getchar()) != 'q')    {        switch(c)        {        case 'a':            CallMyFun(MyFunA,2);            break;        case 'b':            CallMyFun(MyFunB,2);            break;        case 'c':            CallMyFun(MyFunC,2);            break;        }    }    return 0;}void CallMyFun(FunType fp,int x){    fp(x);}void MyFunA(int x){    printf("%d\n",10+x);}void MyFunB(int x){    printf("%d\n",10-x);}void MyFunC(int x){    printf("%d\n",10*x);}

11

#include <stdio.h>#include <stdlib.h>#include <math.h>#define LEN 5typedef double(*MyFun)(double);void transform(double source[],double target[],int len,MyFun);double add1(double x);double reduce1(double x);int main(void){    double source[LEN] = {1.1,1.2,1.3,1.4,1.5};    double target[LEN];    //sin正弦    transform(source,target,LEN,sin);    //cos余弦    transform(source,target,LEN,cos);    transform(source,target,LEN,add1);    transform(source,target,LEN,reduce1);    return 0;}void transform(double source[],double target[],int len,MyFun s){    int i;    for(i=0; i<len; i++)    {        target[i] = s(source[i]);        printf("%lf",target[i]);    }}double add1(double x) {    return x+1;}double reduce1(double x) {    return x-1;}