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c++primerplus(第六版)编程题——第6章(分支语句和逻辑运算符)

声明:作者为了调试方便,每一章的程序写在一个工程文件中,每一道编程练习题新建一个独立文件,在主函数中调用,我建议同我一样的初学者可以采用这种方式,调试起来会比较方便。

(具体方式参见第3章模板)

1.编写一个小程序,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>using namespace std;void cprimerplus_exercise_6_1(){    char letter;    cout << "Please input letters:";    cin >> letter;    cin.get();        while ( letter != @)    {        if (isdigit(letter))        {            cin.get(letter);        }        else        {            if (islower(letter))            {                letter = toupper(letter);            }else if (isupper(letter))            {                letter = tolower(letter);            }            cout << letter;            cin >> letter;            cin.get();        }            }    }

2.编写一个程序,最多将10个donation值读入到一个double数组中(如果你愿意,也可以使用模板类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 <cctype>using namespace std;void cprimerplus_exercise_6_2(){    double donation[10];    double sum = 0.0;    double average = 0.0;    double tmp;     int i = 0;    int cnt = 0;        while ( cin >> tmp && i < 10)    {        donation[i] = tmp;        sum +=donation[i];        ++i;    }    if ( i != 0)    {        average = sum / i;    }    for (int j = 0; j < i; j++)    {        if (donation[j] > average)        {            ++cnt;        }    }    cout << "The average is:" << average << endl;    cout << "There are " << cnt << " numbers are above the average!"<< endl;}

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的操作。

#include <iostream>using namespace std;void cprimerplus_exercise_6_3(){    cout << "Please enter one of the following choices:" << endl        <<"c) carnivore  \tp) pianist \nt) tree \tg) game" << endl;    cout << "Please enter a c, p, t, or g:";    char letter;    cin >> letter;    while ( letter != c && letter != p && letter != t && letter != g)    {                cout << "Please enter a c, p, t, or g:";        cin >> letter;    }    switch (letter)    {    case c:        cout << "A maple is a carnivore";        break;    case p:        cout << "A maple is a pianist";    case t:        cout << "A maple is a tree";        break;    case g:        cout << "A maple is a game";        break;    default:        break;    }}
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姓名来了解他,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,请使用下面结构

//Benevolent Order of Programmers name structure

Struct bop

{

char fullname[strsize];

char title[strsize];

char bopname[strsize];

int preference;

};

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

#include <iostream>using namespace std;void cprimerplus_exercise_6_4(){    const int strsize = 20;    const int mennum = 3;    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    };    bop member[mennum] = {        { "thm", "leader", "sb", 0},        { "cgf", "sb", "sb", 1},        { "th", "dsb", "ssb", 2} };    cout << "Enter your choice!";    char ch;    cin.get(ch);    while (cin >> ch && ch != q)    {        switch (ch)        {        case a:            for (int i = 0; i < mennum; i++)                cout << member[i].fullname << endl;            break;        case b:            for (int i = 0; i < mennum; i++)                cout << member[i].title << endl;            break;        case c:            for (int i = 0; i < mennum; i++)                cout << member[i].bopname << endl;            break;        case d:            for (int i = 0; i < mennum; i++)            {                if (member[i].preference == 0)                {                    cout << member[i].fullname << endl;                }else if (member[i].preference = 1)                {                    cout << member[i].title << endl;                }else if (member[i].preference = 2)                {                    cout << member[i].bopname << endl;                }            }            break;        default:            break;        }        cout << "Next choice:";    }    cout << "Bye!\n";    }
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:10%

如:收入38000 tvarps,所得税:5000*0.0+10000*0.1+20000*0.15+3000*0.2;

#include <iostream>using namespace std;void cprimerplus_exercise_6_5(){    cout << "please input your income:";    double income, revenue;    while (cin >> income && income >= 0)    {        if (income <= 5000)        {            revenue = 0.0;        }else if ( income > 5000 && income <= 15000)        {            revenue = (income - 5000) * 0.1;        }else if( income > 15000 && income < 35000)        {            revenue = 5000 * 0.00 + 10000 * 0.10 + (income -20000) * 0.15;        }else if( income > 35000)        {            revenue = 5000 * 0.00 + 10000 * 0.10 + + 20000 * 0.15 + (income -35000) * 0.15;        }        cout << "your revenue is:" << revenue << endl;        cout << "please enter your income:";    }}

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,这些信息都被存储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的捐款者的姓名以及捐款的数额。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。如果某类别没有捐款人,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;void cprimerplus_exercise_6_6(){    int num;    cout << "please input the donate num:";    cin >> num;    cin.get();    struct patron    {        string name;        double money;    };    patron *ps = new patron[num];        for (int i = 0; i < num; ++i)    {        cout <<"please input the "<< i+1 <<"th patron name:";        getline(std::cin, ps[i].name);        cout << "please input the " << i+1 << "th patron money:";        cin >> ps[i].money;        cin.get();    }    int cnt = 0, snt = 0;    cout << "Grand Patrons:" << endl ;    for (int i = 0; i < num; i++)    {        if (ps[i].money >= 10000)        {            cout <<  ps[i].name << \t <<ps[i].money << endl;            ++cnt;        }    }    if ( cnt == 0)    {        cout << "none";    }    cout << "\nPatrons:" << endl;    for (int i = 0; i < num; i++)    {        if (ps[i].money < 10000)        {            cout << ps[i].name << \t << ps[i].money << endl;            ++snt;        }    }    if ( snt == 0)    {        cout << "none";    }    delete []ps;}

7.编写一个程序,他每次读取一个单词,直到用户只输入q。然后,该程序指出有多少单词以元音打头,有多少个单词以辅音打头,还有多少单词不属于这两类。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salpha()测试的单词,使用if或switch语句来确定哪些是以元音打头。

#include <iostream>#include <string>#include <ctype.h>using namespace std;void cprimerplus_exercise_6_7(){    string word;    cout << "Enter words (q to quit):";    int cnt = 0;    int vowel = 0, constant = 0, other = 0;    while (cin >> word && !word.empty())    {        if(isalpha(word[0]))        {            if (word[0] == q && word.length() == 1)                break;            else if( word[0] == a || word[0] == e || word[0] == i || word[0] == o || word[0] == u)            {                ++vowel;            }else            {                ++constant;            }        }else        {            ++other;        }    }    cout << vowel << " words beginning with vowels "<<  endl;    cout << constant <<" words beginning with constants " << endl;    cout << other  <<" others"  << endl;}

8.编写一个程序,它打开一个文件夹,逐个字符的读取该文件,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>#include <cstdlib>using namespace std;void cprimerplus_exercise_6_8(){    char ch;    int sum = 0;    ifstream inFile;    inFile.open("1.txt");    if( !inFile.is_open())    {        cout << "Could not open the file!\n";        cout << "Program terminating.\n";        exit(EXIT_FAILURE);    }    inFile >> ch;    while (inFile.good())    {        ++sum;        inFile >> ch;    }    if (inFile.eof())    {        cout << "End of file reached.\n";    }else if(inFile.fail())    {        cout << "Input terminated by data mismatch.\n";    }else    {        cout << "Input terminated for unknown reason.\n";    }    cout << "there are " << sum << " chars in this file!\n";}

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。及该文件类似于下面:

4
Sam Stone
2000
Freida Flass
10050
Tammy Tubbs
5000
Rich Raptor
5500

#include <iostream>#include <fstream>#include <string>#include <cstdlib>using namespace std;const int SIZE = 60;void cprimerplus_exercise_6_9(){    char filename[SIZE];    ifstream inFile;    cout << "Enter the name of the file: ";    cin.getline(filename,SIZE);    inFile.open(filename);    if (!inFile.is_open())    {        cout << "Could not open the file" << filename << endl;        cout << "Program terminating.\n";        exit(EXIT_FAILURE);    }    struct patron    {        string name;        double money;    };     int num, cnt = 0, snt = 0;    inFile >> num;    inFile.get();    patron *ps = new patron[num];    for (int i = 0; i < num; i++)    {        getline(inFile, ps[i].name);        inFile >> ps[i].money;        inFile.get();    }    cout << "Grand patrons:\n";    for (int i = 0; i < num; i++)    {        if (ps[i].money >= 10000)        {            cout << ps[i].name <<  \n << ps[i].money << endl;            ++cnt;        }    }    if ( cnt == 0)    {        cout << "none";    }    cout << "\nPatrons:" << endl;    for (int i = 0; i < num; i++)    {        if (ps[i].money < 10000)        {            cout << ps[i].name << \t << ps[i].money << endl;            ++snt;        }    }    if ( snt == 0)    {        cout << "none";    }    delete []ps;    inFile.close();}