第六章 編程練習（1-5）

編程練習1

#include <iostream>
using namespace std;

int main()
{
    char ch;
    cout << "Please type here: " ;
    cin.get(ch);
    while(ch !='@')
    {
        if (isdigit(ch))
        {
            cin.get(ch);
            continue;
        }
        else if(isupper(ch))
            ch = tolower(ch);
        else if(islower(ch))
            ch = toupper(ch);
        cout << ch;
        cin.get(ch);
    }
    cout << endl;

    system("pause");
    return 0;
}

編程練習2

#include <iostream>
using namespace std;

const int MAX = 10;
int main()
{
    double donation[MAX];
    cout << "Please enter the each donation." << endl;
    cout << "You may enter up to " << MAX << " times <type alphabeta to terminate> " << endl;
    cout << "donation #1: ";
    int i = 0;
    while(i < MAX && cin>>donation[i]) {
        if (++i < MAX)
            cout << "donation #" << i+1 << ": ";
    }

    double total = 0;
    for (int j=0; j<i; j++)
        total += donation[j];


    if (i == 0)
        cout << "No donation" << endl;
    else
    {
        int num_above = 0;
        for (int j=0; j<i; j++)
        { 
            if (donation[j] >total/i)
            num_above++;
        }
        cout << "average donation of " << i << " donations is " <<total / i << endl;
        cout << num_above << " donation are above average" << endl;
    }


    system("pause");
    return 0;
}

編程練習3

#include <iostream>
using namespace std;

int main()
{
    char choice;
    cout << "Please enter one of the following choices:" << endl;
    cout << "c) canivore\t" << "p) pianist\t" << endl;
    cout << "t) tree    \t" << "g) game\t" << endl;
    bool flag = true;
    while(flag)
    {
        cout<<"Please enter c,p,t,or g:";  
        cin.get(choice);
        switch(choice) {
        case 'c': cout << " canivore is selected"; flag = false;break;
        case 'p': cout << " pianist is selected"; flag = false;break;
        case 't': cout << " tree is selected"; flag = false;break;
        case 'g': cout << " t is selected"; flag = false;break;
        }
    }
    cout << endl;
    system("pause");
    return 0;
}

編程練習4

#include <iostream>

const int strsize = 30;
struct bop {
    char fullname[strsize];
    char title[strsize];
    char bopname[strsize];
    int preference; // 0 = fullname; 1 = title; 2 = bopname
};

int main()
{
    using namespace std;
    bop arrBop[3] = {
        {"Wimp Mcho","Junir Programmer", "WM",0},
        {"Raki Rhodes","HR", "RR",1},
        {"Celia Laiter","General Manager", "CL",2},
    };

    cout << "Benevolent Order of Programmers Report" << endl;
    cout << "a. display by name   \t" << "b. display by title" << endl;
    cout << "c. display by bopname\t" << "d. display by preference" << endl;
    cout << "q. quite" << endl;
    char choice;
    bool flag = true;

    while(flag)
    {
        cout << "Enter your choice: ";
        cin >> choice;
        switch (choice) {
        case 'a': 
            { 
                for(int i=0; i<3; i++)
                    cout << arrBop[i].fullname << endl;
                break;
            }
        case 'b':
            {
                for(int i=0; i<3; i++)
                    cout << arrBop[i].title << endl;
                break;
            }
        case 'c':
            {
                for(int i=0; i<3; i++)
                    cout << arrBop[i].bopname << endl;
                break;
            }
        case 'd':
            {
                for(int i=0; i<3; i++)
                {
                    switch (arrBop[i].preference) {
                        case 0: cout << arrBop[i].fullname << endl;break;
                        case 1: cout << arrBop[i].title << endl;break;
                        case 2: cout << arrBop[i].bopname <<endl;break;
                    }
                }
                break;
            }
        case 'q':
            {
                flag = false;
                cout << "\nBye";
                break;
            }
        }
    }

    system("pause");
    return 0;
}

編程練習5

#include <iostream>

int main()
{
    using namespace std;
    double income;
    double tax;
    cout << "Please input your incoming: ";
    cin >> income;
    while(cin && income > 0)
    {
        if (income <=5000)
        {
            tax = 0;
        }
        else if (income > 5000 && income <=15000)
        {
            tax = (income-5000) * 0.1 ;
        }
        else if (income > 15000 && income <=35000)
        {
            tax = (income-15000) * 0.15 + 10000 * 0.1;
        }
        else if (income >35000)
        {
            tax = (income-35000) * 0.2 + 20000 * 0.15 + 10000 * 0.1;
        }
        cout << "You should pay " << tax << " as tax" << endl;
        cout << "Please input your incoming: ";
        cin >> income;
    }

    cin.get();
    system("pause");
    return 0;
}