《C++ Primer Plus》（第6版）第6章编程练习
- 《C++ Primer Plus》（第6版）第6章编程练习
- 1. 大小写转换
- 2. 平均值
- 3. 菜单
- 4. 成员
- 5. 收入所得税
- 6. 捐款
- 7. 统计单词
- 8. 统计文件字符数
- 9. 重写编程练习6
《C++ Primer Plus》（第6版）第6章编程练习
1. 大小写转换
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)。
代码：
#include <iostream>
#include <cctype>
using namespace std;int main()
{char c;cout << "Enter text for analysis(enter @ to quit):\n";while (cin >> c && c != '@'){if (islower(c))c = toupper(c);else if (isupper(c))c = tolower(c);if (!isdigit(c))cout << c;}cout << "Done!\n";system("pause");return 0;
}
2. 平均值
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。
代码：
#include <iostream>
#include <array>
using namespace std;
#define ArrSize 10int main(void)
{array<double, ArrSize> donation;cout << "Enter the elements you want to exist in the array "<< "( a non number input to terminate):" << endl;int i = 0;double sum = 0;int elem = 0;int count = 0;while (i < ArrSize && cin >> donation[i]){elem++;sum += donation[i];i++;}double average = sum / elem;for (i = 0; i < ArrSize; i++){if (donation[i] > average)count++;}cout << "average = " << average << endl;cout << count << " numbers greater than average.\n";system("pause");return 0;
}
运行结果：
3. 菜单
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: qPlease enter a c, p,t, or g: tA maple is a tree.
代码：
#include <iostream>
using namespace std;
int main()
{char ch;cout << "Please enter one of the following choices:" << endl;cout << "c) carnivore p) pianist" << endl;cout << "t) tree g) game" << endl;while (cin >> ch){switch (ch){case 'c':cout << "A tiger is a carnivore." << endl;break;case 'p':cout << "Langlang is a pianist." << endl;break;case 't':cout << "A maple is a tree." << endl;break;case 'g':cout << "Golf is a game." << endl;break;default:cout << "Please enter a c, p, t, or g: ";}}system("pause");return 0;
}
运行结果：
4. 成员
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姓名来了解他（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 Programmers name structure
struct bop {
char fullname [strsize] ;// real namechar 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 of Programmers 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
LOOFY
Next choice: q
Bye!
代码：
#include <iostream>
using namespace std;
#define LEN 5
#define strsize 20
// Benevolent Order of Programmers name structure
struct bop
{char fullname[strsize]; // real namechar title[strsize]; // job titlechar bopname[strsize]; // secret BOP nameint preference; // 0 = fullname，1 = title， 2 = bopname);
};void display_by_name(bop *);
void display_by_title(bop *);
void display_by_bopname(bop *);
void display_by_preference(bop *);int main()
{char ch;bop member[LEN] ={{"Wimp Mache", "BOSS", "AS", 0},{"Raki Rhodes", "Junior Programmer", "MA", 1},{"Celia Laiter", "Manager", "MIPS", 2},{"Hoppy Hipman", "Analyst Trainee", "CL", 1},{"Pat Hand", "Student", "LOOPY", 2}};cout << "Benevolent Order of Programmers Report\n";cout << "a. display by name b. display by title\n";cout << "c. display by bopname d. display by preference\n";cout << "q. quit\n";cout << "Enter your choice: ";while (cin >> ch && ch != 'q'){switch (ch){case 'a':display_by_name(member);break;case 'b':display_by_title(member);break;case 'c':display_by_bopname(member);break;case 'd':display_by_preference(member);break;}cout << "Next choice: ";}cout << "Bye!\n";system("pause");return 0;
}
void display_by_name(bop *b)
{for (int i = 0; i < LEN; i++)cout << b[i].fullname << endl;
}
void display_by_title(bop *b)
{for (int i = 0; i < LEN; i++)cout << b[i].title << endl;
}
void display_by_bopname(bop *b)
{for (int i = 0; i < LEN; i++)cout << b[i].bopname << endl;
}
void display_by_preference(bop *b)
{for (int i = 0; i < LEN; i++){switch (b[i].preference){case 0:cout << b[i].fullname << endl;break;case 1:cout << b[i].title << endl;break;case 2:cout << b[i].bopname << endl;break;}}
}
运行结果：
5. 收入所得税
在 Ncutronia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。
代码：
#include <iostream>
using namespace std;
#define RATE1 0.10
#define RATE2 0.15
#define RATE3 0.20
double cal_tax(int);
int main()
{int income;double tax;cout << "Enter your income(enter negative number or q to quit): ";while (cin >> income && income >= 0){cout << "your tax is " << cal_tax(income) <<".\n";cout << "Enter your income: ";}system("pause");return 0;
}
double cal_tax(int x)
{double tax;if (x <= 5000)tax = 0.0;else if (x <= 15000)tax = RATE1 * (x - 5000);else if (x <= 35000)tax = RATE1 * (15000 - 5000) + RATE2 * (x - 15000);elsetax = RATE1 * (15000 - 5000) + RATE2 * (35000 - 15000) + RATE3 * (x - 35000);return tax;
}
运行结果：
6. 捐款
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献者数目，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:用来储存姓名的字符数组（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的捐款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。如果某种类别没有捐款者，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。
代码：
#include <iostream>
#include <cstring>
using namespace std;
struct Donor
{string name;double money;
};void showGrand(Donor *, int);
void showOther(Donor *, int);int main()
{int num = 0;cout << "How many donors are there? ";cin >> num;cin.get(); // 清除缓存Donor *donor = new Donor[num];for (int i = 0; i < num; i++){cout << "Please enter the " << i + 1 << "-th name: ";getline(cin, donor[i].name);cout << "Please enter the " << i + 1 << "-th money: ";cin >> donor[i].money;cin.get();}cout << "Grand Patrons:\n";showGrand(donor, num);cout << "Patrons:\n";showOther(donor, num);system("pause");return 0;
}void showGrand(Donor *d, int num)
{int count = 0;for (int j = 0; j < num; j++){if (d[j].money > 10000){cout << d[j].name << "\t" << d[j].money << endl;count++;}}if (count == 0)cout << "none\n";
}void showOther(Donor *d, int num)
{int count = 0;for (int j = 0; j < num; j++){if (d[j].money <= 10000){cout << d[j].name << "\t" << d[j].money << endl;count++;}}if (count == 0)cout << "none\n";
}运行结果：
7. 统计单词
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( )来区分以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 with consonants
2 others
代码：
#include <iostream>
#include <cstring>
#include <cctype>
using namespace std;#define ArrSize 30int main(void)
{char str[ArrSize];int count_other = 0, count_vowel = 0, count_consonant = 0;cout << "Enter words(q to quit) :" << endl;while (cin >> str){if (strcmp(str, "q") == 0)break;char ch = str[0];if (isalpha(ch)){switch (ch){case 'a':case 'e':case 'i':case 'o':case 'u':count_vowel++;break;default:count_consonant++;}}elsecount_other++;}cout << count_vowel << " words beginning with vowels\n";cout << count_consonant << " words beginning with consonants\n";cout << count_other << " others\n";system("pause");return 0;
}
运行结果：
8. 统计文件字符数
编写一个程序，它打开一个文件文件，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。
代码：
#include <iostream>
#include <fstream>
#include <cstdlib>
using namespace std;#define SIZE 60int main()
{char filename[SIZE];ifstream inFile;cout << "Enter name of data file:";cin.getline(filename, SIZE);inFile.open(filename);if (!inFile.is_open()){cout << "Could not open the file " << filename << endl;cout << "Program terminating." << endl;exit(EXIT_FAILURE);}int count = 0;char ch;inFile >> ch;while (inFile.good()){count++;inFile >> ch;// cout << ch;}if (inFile.eof())cout << "End of file reached." << endl;else if (inFile.fail())cout << "Input terminated by data mismatch." << endl;elsecout << "Input terminated for unknown reason." << endl;cout << "A total of " << count << " characters were read." << endl;inFile.close();system("pause");return 0;
}
运行结果：
9. 重写编程练习6
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
100500
Tammy Tubbs
5000
Rich Raptor
55000
代码：
#include <iostream>
#include <cstring>
#include <fstream>
using namespace std;#define SIZE 30struct Donor
{string name;double money;
};void showGrand(Donor *, int);
void showOther(Donor *, int);int main()
{char fileName[SIZE];ifstream infile;int num = 0;cout << "Enter the filename: ";cin.getline(fileName, SIZE);infile.open(fileName);if (!infile.is_open()){cout << "Can't open file " << fileName << endl;cout << "program terminating." << endl;exit(EXIT_FAILURE);}infile >> num;infile.get(); // 清除缓存Donor *donor = new Donor[num];for (int i = 0; i < num; i++){getline(infile, donor[i].name);infile >> donor[i].money;infile.get(); // 清除缓存}cout << "Grand Patrons:\n";showGrand(donor, num);cout << "Patrons:\n";showOther(donor, num);system("pause");return 0;
}void showGrand(Donor *d, int num)
{int count = 0;for (int j = 0; j < num; j++){if (d[j].money > 10000){cout << d[j].name << "\t" << d[j].money << endl;count++;}}if (count == 0)cout << "none\n";
}void showOther(Donor *d, int num)
{int count = 0;for (int j = 0; j < num; j++){if (d[j].money <= 10000){cout << d[j].name << "\t" << d[j].money << endl;count++;}}if (count == 0)cout << "none\n";
}运行结果：
