1. 编写一个程序，读取键盘输入，直到遇到@符号为止，并回显输入（数字除外），同时将大写字符转换为小写，将小写字符转换为大写（别忘了cctype函数系列）。

 

#include<iostream> #include<cctype>//prototypes for character functions using namespace std; int main() {     char ch;//定义一个char类型变量     cout << "Enter the character,and type @"<<endl;     cin.get(ch);     while (ch != '@ ')     {          if (isdigit(ch))//当输入的是数字时          {              cin.get(ch);//输出数字              continue;          }         else if (islower(ch))//当输入的是小写字母时          {              ch = toupper(ch);//小写 -> 大写          }          else if (isupper(ch))//当输入的是大写字母时          {              ch = tolower(ch);//大写 -> 小写          }          cout << ch ;          cin.get(ch);              }     system("pause");     return 0; } //Enter the character, and type @ //@ //@ //china //CHINA // // //CHINA //china

2. 编写一个程序，最多将10个donation值读入到一个double数组中（如果您愿意，也可使用模板类array）。程序遇到非数字输入时将结束输入，并报告这些数字的平均值以及数组中有多少个数字大于平均值。

#include<iostream> #include<array> using namespace std; int main() {     array<double, 10> donation;//使用array模板定义数组长度为10     double input;     int counter = 0;     double average, sum = 0;     int bigger = 0;     //sum ->和 average ->平均值 counter ->元素数 bigger->大于平均值的个数     cout << "Enter the double numerical:";     cin >> input;     while (input != 0 && counter < 10)     {          donation[counter++] = input;          cout << "No." << counter << " Data input to Array." << endl;          cout << "Enter the double numerical.";          cin >> input;     }//通过while循环输入数据，当输入非数字时或超过10个元素时推出循环     for (int i = 0; i < counter; i++)     {          sum += donation[i];//十个数的总和     }     average = sum / counter;     for (int i = 0; i < counter; i++)     {          if (donation[i] > average)              bigger++;     }//通过遍历计算大于平均值的元素个数     cout << "The Average is " << average << " and " << bigger;     cout << " data bigger than average." << endl;     system("pause");     return 0; } //Enter the double numerical : 10 //No.1 Data input to Array. //Enter the double numerical.20 //No.2 Data input to Array. //Enter the double numerical.30 //No.3 Data input to Array. //Enter the double numerical.40 //No.4 Data input to Array. //Enter the double numerical.50 //No.5 Data input to Array. //Enter the double numerical.60 //No.6 Data input to Array. //Enter the double numerical.70 //No.7 Data input to Array. //Enter the double numerical.80 //No.8 Data input to Array. //Enter the double numerical.90 //No.9 Data input to Array. //Enter the double numerical.100 //No.10 Data input to Array. //Enter the double numerical.110 //The Average is 55 and 5 data bigger than average. //请按任意键继续. . .

3. 编写一个菜单驱动程序的雏形。该程序显示一个提供4个选项的菜单——每个选项用一个字母标记。如果用户使用有效选项之外的字母进行响应，程序将提示用户输入一个有效的字母，直到用户这样做为止。然后，该程序使用一条switch语句，根据用户的选择执行一个简单操作。该程序的运行情况如下：

Please enter one of the following choices:

c) carnivore            p) pianist

t) tree                     g) game

f

Please enter a c, p, t, or g: q

Please enter a c, p, t, or g: t

A maple is a tree.

#include<iostream> using namespace std; void showmenu();//showmenu()函数声明 int main() {     char choice;     showmenu();     cin.get(choice);//显示菜单，并读取用户输入，保存至choice变量中     while (choice != 'c' && choice != 'p' && choice != 't' && choice != 'g')     {          cin.get();          cout << "Please enter a,c,p,t,or g ";          cin.get(choice);     }     switch (choice)     {     case'c':          break;     case'p':          break;     case't':          cout << "Asample is a tree." << endl;     case'g':          break;     }     system("pause");     return 0; } void showmenu() {     cout << "Please enter one of the following choice:\n";     cout << "c) carnivore \t\t\t p) pianist\n";     cout << "t) tree\t\t\t\t g)game\n"; }//showmenu()函数只负责菜单传递信息的输出 //Please enter one of the following choice : //c) carnivore                     p) pianist //t) tree                          g)game //f //Please enter a, c, p, t, or g q //Please enter a, c, p, t, or g t //Asample is a tree. //请按任意键继续. . .

4. 加入Benevolent Order of Programmer后，在BOP大会上，人们便可以通过加入者的真实姓名、头衔或秘密BOP姓名了解他（她）。请编写一个程序，可以使用真实姓名、头衔、秘密姓名或成员偏好来列出成员。编写该程序时，请使用下面的结构：

// Benevolent Order of Programmer name structure

struct bop {

    char fullname[strsize];      // real name

    char title[strsize];              // job title

    char bopname[strsize];     // secret BOP name

    int preference;                  // 0 = fullname, 1 = title, 2 = bopname

};

该程序创建一个由上述结构组成的小型数组，并将其初始化为适当的值。另外，该程序使用一个循环，让用户在下面的选项中进行选择：

a. display by name        b. display by title

c. display by bopname  d. display by preference

q. quit

注意，“display by preference”并不意味着显示成员的偏好，而是意味着根据成员的偏好来列出成员。例如，如果偏好号为1，则选择d将显示程序员的头衔。该程序的运行情况如下：

Benevolent Order Programmer Report

a. display by name        b. display by title

c. display by bopname  d. display by preference

q. quit

Enter your choice: a

Wimp Macho

Raki Rhodes

Celia Laiter

Hoppy Hipman

Pat Hand

Next choice: d

Wimp Macho

Junior Programmer

MIPS

Analyst Trainee

LOOPY

Next choice: q

Bye!

这题不会直接抄答案。

#include<iostream> #include<cstring> using namespace std; const int strsize = 40; const int usersize = 5; //Benevolent Order of Programmer 姓名结构体 struct bop {     char fullname[strsize];//真实姓名     char title[strsize];//头衔     char bopname[strsize];//秘密BOP姓名     int preference;//0 = fullname,1 = title;2 = bopname }; bop bop_user[usersize] = {     {"Wimp Macho","Programmer","MIPS",0},     {"Raki Rhodes","Junior Programmer",1},     {"Celia Laiter","","MIPS",2},     {"Hoppy Hipman","Analyst Trainee","",1},     {"Pat Hand","","LOOPY",2}, };//定义常量，定义结构体初始化bop数组信息 void showmenu();//showmenu()函数声明 void print_by_name();//打印姓名函数声明 void print_by_pref();//打印偏好函数声明 void print_by_title();//打印头衔函数声明 void print_by_bopname();//打印秘密姓名函数声明 void create_info(); int main() {     char choice;     //create_info();     showmenu();     cout << "Enter your choice:";     cin.get(choice);//显示菜单读取用户输入     while (choice != 'q')     {          switch (choice)          {          case 'a':              print_by_name();              break;          case 'b':              print_by_title();              break;          case 'c':              print_by_bopname();              break;          case 'd':              print_by_pref();              break;          default:              cout << "Please enter character a ,b ,c ,d , or q:" << endl;          }          //通过switch语句对应的函数进行显示          cout << "Next choice:";          cin.get(choice);     }     //将switch语句放在while循环中，可以反复循环给下那个功能     cout << "Bye!" << endl;     system("pause");     return 0; } void showmenu() {     cout << "a. display by name\t\t b. display by title" << endl;     cout << "c. display by bopname\t\t d. display by preference" << endl;     cout << "q. quit" << endl; }//显示菜单 void print_by_name() {     for (int i = 0; i < usersize; i++)     {          if (bop_user[i].fullname == 0)              break;          else              cout << bop_user[i].fullname << endl;     } } void print_by_pref() {     for (int i = 0; i < usersize; i++)     {          if (bop_user[i].fullname == 0)              break;          else          {              switch (bop_user[i].preference)              {              case 0:                   cout << bop_user[i].fullname << endl;                   break;              case 1:                   cout << bop_user[i].title << endl;                   break;              case 2:                   cout << bop_user[i].bopname << endl;                   break;              }          }     } } void print_by_title() {     for (int i = 0; i < usersize; i++)     {          if (bop_user[i].fullname == 0)              break;          else          {              cout << bop_user[i].title << endl;              break;          }     } } void print_by_bopname() {     for (int i = 0; i < usersize; i++)     {          if (bop_user[i].fullname == 0)              break;          else          {              cout << bop_user[i].bopname << endl;              break;          }     } } void create_info() {     for (int i = 0; i < usersize; i++)     {          cout << "Enter the user's full name:";          cin.getline(bop_user[i].fullname, strsize);          cout << "Enter the user's title:";          cin.getline(bop_user[i].title, strsize);          cout << "Enter the user's bopname:";          cin.getline(bop_user[i].bopname, strsize);          cout << "Enter the user's preference:";          cin >> bop_user[i].preference;          cout << "Next...(f for finished):";          cin.get();          if (cin.get() == 'f') break;     } } //a.display by name               b.display by title //c.display by bopname            d.display by preference //q.quit //Enter your choice : a //Wimp Macho //Raki Rhodes //Celia Laiter //Hoppy Hipman //Pat Hand //Next choice : Please enter character a, b, c, d, or q : //Next choice : d //Wimp Macho //Raki Rhodes //MIPS //Analyst Trainee //LOOPY //Next choice : Please enter character a, b, c, d, or q : //Next choice : q //Bye! //请按任意键继续. . . 

5. 在Neutronia王国，货币单位是tvarp，收入所得税的计算方式如下：

5000 tvarps：不收税

5001~15000 tvarps：10%

15001~35000 tvarps：15%

35000 tvarps以上：20%

例如，收入为38000 tvarps 时，所得税为5000*0.00+10000*0.10+20000*0.15+3000*0.20，即4600 tvarps。请编写一个程序，使用循环来要求用户输入收入，并报告所得税。当用户输入负数或非数字时，循环将结束。

 

#include<iostream> using namespace std; int main() {     float tax, salary;     cout << "Please enter your salary:";     cin >> salary;     while (salary > 0)     {          if (salary < 5000)          {              tax = 0;          }          else if (salary <= 15000)          {              tax = (salary - 5000) * 0.10;          }          else if (salary <= 35000)          {              tax = 10000 * 0.10 + (salary - 15000) * 0.15;          }          else if (salary > 35000)          {              tax = 10000 * 0.10 + 20000 * 0.15 + (salary - 30000) * 0.20;          }          cout << "Your salary is " << salary << " trarps,and you should pay ";          cout << tax << " trarps of tax." << endl;          cout << "Enter your salary:";          cin >> salary;     }     cout << "Bye!" << endl;     system("pause");     return 0; } //Please enter your salary : 4000 //Your salary is 4000 trarps, and you should pay 0 trarps of tax. //Enter your salary : 15000 //Your salary is 15000 trarps, and you should pay 1000 trarps of tax. //Enter your salary : 25000 //Your salary is 25000 trarps, and you should pay 2500 trarps of tax. //Enter your salary : 40000 //Your salary is 40000 trarps, and you should pay 6000 trarps of tax. //Enter your salary : 0 //Bye! //请按任意键继续...

6. 编写一个程序，记录捐助给“维护合法权利团体”的资金。该程序要求用户输入捐赠者数目，然后要求用户输入每一个捐献者的姓名和款项。这些信息被储存在一个动态分配的结构数组中。每个结构有两个成员：用来储存姓名和字符数组（或string对象）和用来存储款项的double成员。读取所有的数据后，程序将显示所有捐款超过10000的捐献者的姓名及其捐款数额。该列表前应包含一个标题，指出下面的捐款者是重要捐款人（Grand Patrons）。然后，程序将列出其他的捐款者，该列表要以Patrons开头。如果某种类型没有捐献者，则程序将打印单词“none”。该程序只显示这两种类别，而不进行排序。

#include<iostream> #include<string> using namespace std; struct patrons {     string full_name;     double fund; };//捐款人基本信息的结构体 int main() {     int patrons_number;     patrons *ppatrons;     cout << "How many patrons ? ";     cin >> patrons_number;     cin.get();     ppatrons = new patrons[patrons_number];//建立动态数组     int id = 0;     bool empty = true;     cout << "Starting to input patron's info:";     while (id < patrons_number)     {          cout << "Enter the full name of patrons: ";          getline(cin, ppatrons[id].full_name);          cout << "Enter the fuud of " << ppatrons[id].full_name << " : ";          cin >> ppatrons[id].fund;          cin.get();          id++;          cout << "Continue to input,or press (f) to finished.";          if (cin.get() == 'f')              break;     }//建立捐款人名单     cout << "Grand Patrons" << endl;     for (int i = 0; i < patrons_number; i++)     {          if (ppatrons[i].fund >= 1000) {              cout << ppatrons[i].full_name << " : " << ppatrons[i].fund << endl;              empty = false;          }     }     //查询Grand Patrons名单，如果empty为true，输出NONE     if (empty)          cout << "NONE" << endl;     empty = false;     cout << "Patrons" << endl;     for (int i = 0; i < patrons_number; i++)     {          if (ppatrons[i].fund < 1000) {              cout << ppatrons[i].full_name << " : " << ppatrons[i].fund << endl;          }     }     if (empty)          cout << "NONE" << endl;     system("pause");     return 0; } //How many patrons ? 2 //Starting to input patron's info:Enter the full name of patrons: LI MING //Enter the fuud of LI MING : 5000 //Continue to input, or press(f) to finished. //Enter the full name of patrons : LI HUA //Enter the fuud of LI HUA : 1000 //Continue to input, or press(f) to finished.f //Grand Patrons //LI MING : 5000 //LI HUA : 1000 //Patrons //请按任意键继续. . .

7. 编写一个程序，它每次读取一个单词，直到用户只输入q。然后，该程序指出有多少个单词以元音打头，有多少个单词以辅音打头，还有多少个单词不属于这两类。为此，方法之一是，使用isalpha()来区分字母和其他字符打头的单词，然后对于通过了isalpha()测试的单词，使用if或switch语句来确定哪些以元音打头。该程序的运行情况如下：

Enter words (q to quit):

The 12 awesome oxen ambled

quietly across 15 meters of lawn. q

5 words beginning with vowels

4 words beginning consotants

2 others

#include<iostream> #include<cctype> using namespace std; int main() {     char words[40];     int vowel, consonant, others;     vowel = consonant = others = 0;     cout << "Enter words(q to quit):" << endl;     cin >> words;     while (strcmp(words, "q") != 0)     {          if (!isalpha(words[0]))          {              others++;          }//统计非字母开头的单词          else {              switch (words[0])              {              case 'a':              case 'e':              case 'i':              case 'o':              case 'u':                   vowel++;//统计以元音字母开头的单词                   break;              default:                   consonant++;//统计非元音字母开头的单词              }          }          cin >> words;     }     cout << vowel << " words beginning with vowel." << endl;     cout << consonant << " words beginning with consonants." << endl;     system("pause");     return 0; } //Enter words(q to quit) : //The 12 awesome oxen ambled //quitely across 15 meters of lawn //q //5 words beginning with vowel. //4 words beginning with consonants. //请按任意键继续. . .

8. 编写一个程序，它打开一个文件，逐个字符地读取该文件，直到到达文件末尾，然后指出该文件中包含多少个字符。

#include<iostream> #include<fstream> using namespace std; int main() {     ifstream fin;//定义文件输入流     string file_name;     cout << "Enter the file name:";     getline(cin, file_name);     fin.open(file_name);     if (!fin.is_open()) {          cout << "Error to open file." << endl;          exit(EXIT_FAILURE);     }     char read_char;     int char_counter = 0;     while (!fin.eof()) {          fin >> read_char;          char_counter++;     }     cout << "The file " << file_name << " contains " << char_counter << " characters." << endl;     fin.close();//关闭文件     system("pause");     return 0; }

建立txt文件如下所示：

9. 完成编程练习6，但从文件中读取所需的信息。该文件的第一项应为捐款人数，余下的内容应为成对的行。在每一对中，第一行为捐款人姓名，第二行为捐款数额。即该文件类似于下面：

4

Sam Stone

2000

Freida Flass

Tammy Tubbs

5000

Rich Raptor

55000

#include <iostream> #include <fstream> #include<string> using namespace std; struct patrons {     string full_name;     double fund; }; //表示捐款人信息的结构体 int main() {     ifstream fin;     string file_name;     cout << "Enter the file name:";     getline(cin, file_name);     fin.open(file_name);     if (!fin.is_open())     {          cout << "Error to open file:" << endl;          exit(EXIT_FAILURE);     }     int patrons_number;     patrons *ppatrons;     int id = 0;     bool empty = true;     fin >> patrons_number;     if (patrons_number <= 0)     {          exit(EXIT_FAILURE);     }     ppatrons = new patrons[patrons_number];     fin.get();     //读取人数，创建动态数组     while (!fin.eof() && id < patrons_number)     {          getline(fin, ppatrons[id].full_name);          cout << "Read Name: " << ppatrons[id].full_name << endl;          fin >> ppatrons[id].fund;          cout << "Read fund: " << ppatrons[id].fund << endl;          fin.get();          id++;     }     //循环读取捐款人信息，也可以使用for循环     fin.close();//关闭文件     cout << "Grand Patrons" << endl;     for (int i = 0; i < patrons_number; i++)     {          if (ppatrons[i].fund >= 10000) {              cout << ppatrons[i].full_name << " ; " << ppatrons[i].fund << endl;              empty = false;          }     }         if (empty)     cout << "NONE" << endl;     empty = false;     cout << "Patrons" << endl;     for (int i = 0; i < patrons_number; i++)     {          if (ppatrons[i].fund < 10000) {              cout << ppatrons[i].full_name << " : " << ppatrons[i].fund << endl;          }     }     if (empty) cout << "NONE" << endl;     system("pause");     return 0; }

建立txt文件如下所示：