《C++primerplus》第9章练习题_C

概述 1.（未使用原书例题）练习多文件组织。在一个头文件中定义一种学生的结构体，存储姓名和年龄，声明三个函数分别用于询问有多少个学生，输入学生的信息和展示学生的信息。在另一个源文件中给出所有函数的定义。在主程序中使用new初始化结构指针，调用三个函数。 //main.cpp#include<iostream>#include"Extra.h"using namespace std;

1.（未使用原书例题）练习多文件组织。在一个头文件中定义一种学生的结构体，存储姓名和年龄，声明三个函数分别用于询问有多少个学生，输入学生的信息和展示学生的信息。在另一个源文件中给出所有函数的定义。在主程序中使用new初始化结构指针，调用三个函数。

//main.cpp#include<iostream>#include"Extra.h"using namespace std;int main(){    set_student();    student * students_pt = new student[student_num];    input_student(students_pt);    show_student(students_pt);    delete []students_pt;    system("pause");}

//Extra.h#ifndef _EXTRA_H_#define _EXTRA_H_#include<iostream>const int len = 30;struct student{    char name[len];    int age;};extern int student_num;voID set_student();voID input_student(student sdu[]);voID show_student(student sdu[]);#endif // !_EXTRA_H_

//defineExtra.cpp#include<iostream>#include"Extra.h"using namespace std;int student_num = 1;voID set_student(){    cout << "How many students: ";    if (!(cin >> student_num))        cout << "Bad input.";    else {};    cin.get();    //消除换行符，以便cin.get输入}voID input_student(student sdu_i[]){    for (int i = 0; i < student_num; i++)    {        cout << "Enter student" << i + 1 << "‘s name:\n";        cin.get(sdu_i[i].name,len);        cout << "Enter student" << i + 1 << "‘s age:\n";        if(cin >> sdu_i[i].age)            cout << "Bad input.";        else {};        cin.get();      }}voID show_student(student sdu_o[]){    for (int i = 0; i < student_num; i++)    {        cout << "Student " << i + 1 << " | " << sdu_o[i].name << ",age " << sdu_o[i].age;        cout << "\n";    }}

2.（未使用原书例题，对应第四题）修改上题的程序，使用重载函数编写函数的其它版本，并使用命名空间包括和拓展。主程序的运行过程见注释。

//main.cpp#include<iostream>#include"Extra.h"using namespace std;using namespace STU;int main(){    //先询问有几个学生，然后使用new动态创建相应数量的结构体    set_student();    student * students_pt = new student[student_num];    //输入学生的信息并展示    input_student(students_pt);    show_student(students_pt);    //再定义一个student结构体，存储交换生的信息并展示    student stu_transfer;    char st[] = "Joseph";    input_student(stu_transfer,st,18);    show_student(stu_transfer);    delete []students_pt;    system("pause");}

//Extra.h#ifndef _EXTRA_H_#define _EXTRA_H_#include<iostream>#include<cstring>namespace STU{    const int len = 30;    struct student    {        char name[len];        int age;    };    extern int student_num;    voID set_student();    voID input_student(student stu_i_ar[]);    //输入学生信息，交互式版本    voID input_student(student & stu_i,char str[],int age);    //输入学生信息，非交互式版本    voID show_student(const student stu_o_ar[]);    //展示结构体数组信息的版本    voID show_student(const student & stu_o);    //展示单个结构体信息的版本}#endif // !_EXTRA_H_

//defineExtra.cpp#include<iostream>#include"Extra.h"using namespace std;int STU::student_num = 1;voID STU::set_student(){    cout << "How many students: ";    if (!(cin >> STU::student_num))        cout << "Bad input.";    else {};    cin.get();    //消除换行符，以便cin.get输入}voID STU::input_student(student stu_i_ar[]){    for (int i = 0; i < STU::student_num; i++)    {        cout << "Enter student" << i + 1 << "‘s name:\n";        cin.get(stu_i_ar[i].name,STU::len);        cout << "Enter student" << i + 1 << "‘s age:\n";        if(!(cin >> stu_i_ar[i].age))            cout << "Bad input.";        else {};        cin.get();      }}voID STU::input_student(student & stu_i,int age){    strcpy_s(stu_i.name,str);    //编译器提示使用    stu_i.age = age;}voID STU::show_student(const student stu_o_ar[]){    for (int i = 0; i < STU::student_num; i++)    {        cout << "Student " << i + 1 << " | " << stu_o_ar[i].name << ",age " << stu_o_ar[i].age;        cout << "\n";    }}voID STU::show_student(const student & stu_o){    cout << "Trasfer student | " << stu_o.name << ",age " << stu_o.age;}