#include <iostream>

#include <cctype>

using namespace std;

int main()

{

    char in_put;

    do

    {

        cout << "Please enter the letters (enter @ exit):";

        cin >> in_put;

        if (islower(in_put))

            cout << "The uppercase of the letter " << in_put << " is " << char (toupper(in_put)) << ".\n";

        else if (isupper(in_put))

            cout << "The lowercase of the letter " << in_put << " is " << char (tolower(in_put)) << ".\n";

        else if (in_put != '@')

            cout << "Please enter the letters!\n";

    } while (in_put != '@');

    cout << "Exit!\n";

    system("pause");

}

#include <iostream>

using namespace std;

const int MAX = ;

int main()

{

    double in_put[MAX];

    double avg = ;

    int sum;

    cout << "Please enter no more than " << MAX << " digits.\n";

    for (int i = ; i < MAX; ++i)

    {

        cout << "The " << i +  << "th digit is: ";

        if (cin >> in_put[i])

            avg += in_put[i];

        else

        {

            cout << "Not digit! Exit!\n";

            sum = i;

            break;

        }

    }

    avg = avg / sum;

    int num_a=, num_b=;

    for (int i = ; i < sum; ++i)

    {

        if (in_put[i] > avg)

            num_a += ;

        else

            num_b += ;

    }

    cout << "The average of these numbers is: " << avg << ".\n"

        << "There are " << num_a << " numbers larger than the average value.\nAnd "

        << num_b << " numbers not larger than the average value.\n";

    system("pause");

}

#include <iostream>

using namespace std;

int show(char);

int show(char ch)

{

    int flag = ;

    cout << "A maple is a ";

    switch(ch)

    {

    case 'c':

        cout << "carnivore.\n";

        break;

    case 'p':

        cout << "pianist.\n";

        break;

    case 't':

        cout << "tree.\n";

        break;

    case 'g':

        cout << "game.\n";

        break;

    default:

        cout << "Please enter c,p,t,g :";

        flag = ;

    }

    return flag;

}

int main()

{

    char ch;

    int flag;

    cout << "Please enter one of the following choices:\n"

        << "c) carnivore\t" << "p) pianist\n"

        << "t) tree\t\t" << "g) game\n";

    do

    {

        cin >> ch;

        flag=show(ch);

    } while (flag == );

    system("pause");

}

#include <iostream>

using namespace std;

const int strsize = ;

const int MAX = ;

struct bop

{

    char fullname[strsize];

    char title[strsize];

    char bopname[strsize];

    int preference;

};

int show(char ch, bop mmm[MAX])

{

    int flag = ;

    switch (ch)

    {

    case 'a':

        for (int i = ; i < MAX; ++i)

        {

            cout << mmm[i].fullname<<endl;

        }

        break;

    case 'b':

        for (int i = ; i < MAX; ++i)

        {

            cout << mmm[i].title << endl;

        }

        break;

    case 'c':

        for (int i = ; i < MAX; ++i)

        {

            cout << mmm[i].bopname << endl;

        }

        break;

    case 'd':

        for (int i = ; i < MAX; ++i)

        {

            switch(mmm[i].preference)

            {

                case :cout << mmm[i].fullname << endl;

                    break;

                case :cout << mmm[i].title << endl;

                    break;

                case :cout << mmm[i].bopname << endl;

                    break;

            }

        }

        break;

    case 'q':

        flag = ;

        break;

    default:

        cout << "Please enter a,b,c,d,q!\n";

    }

    return flag;

}

int main()

{

    bop all_peo[MAX] =

    {

        { "QQQ","NiCai","qqq", },

        { "WWW","BuCai","www", },

        { "EEE","CaiBuCai","eee", },

        { "RRR","JiuBuCai","rrr", },

        { "TTT","LaDao","ttt", }

    };

    char ch;

    int flag;

    cout << "Benevolent Order of Programmers Report\n"

        << "a. display by name\t" << "b. display by title\n"

        << "c. display by bopname\t" << "d. display by preference\n"

        << "q. quit\n";

    cout << "Enter your choice:";

    cin >> ch;

    flag = show(ch, all_peo);

    while (flag == )

    {

        cout << "Next choice: ";

        cin >> ch;

        flag=show(ch, all_peo);

    }

    cout << "Bye!\n";

    system("pause");

}

#include <iostream>

using namespace std;

const float Tax_1 = 0.1;

const float Tax_2 = 0.15;

const float Tax_3 = 0.2;

const int Tax_come1 = ;

const int Tax_come2 = ;

const int Tax_come3 = ;

double Tax(double);

int main()

{

    double income;

    cout << "Please enter income(enter a negative or non-numeric exit): ";

    while (cin >> income)

    {

        if (income < )

            break;

        double tax;

        tax=Tax(income);

        cout << "Income tax: " << tax << "\nNext enter: ";

    }

    cout << "Bye!\n";

    system("pause");

}

double Tax(double income)

{

    double tax;

    double num1 = income - Tax_come3;

    double num2 = income - Tax_come2;

    double num3 = income - Tax_come1;

    if (num1 > )

        tax =(Tax_come2 - Tax_come1)*Tax_1 + (Tax_come3 - Tax_come2)*Tax_2 + num1 * Tax_3;

    else

    {

        if (num2 > )

            tax =(Tax_come2 - Tax_come1)*Tax_1 + num2 *Tax_2;

        else

        {

            if (num3 > )

                tax = num3 * Tax_1;

            else

                tax = ;

        }

    }

    return tax;

}

#include <iostream>

#include <string>

using namespace std;

struct potron

{

    string name;

    double money;

};

int main()

{

    int num;

    cout << "Please enter the number of donors: ";

    cin >> num;

    potron *potrons = new potron[num];

    for (int i = ; i < num; ++i)

    {

        cout << "Please enter the " << i +  << "th donor name:";

        cin.ignore();

        getline(cin,potrons[i].name);

        cout << "Please enter the number of " << i +  << "th donor contributions:";

        cin >> potrons[i].money;

    }

    int flag1 = , flag2 = ;

    cout << "Grand Potrons\n";

    for (int i = ; i < num; ++i)

    {

        if (potrons[i].money > )

        {

            cout << potrons[i].name << " : " << potrons[i].money << endl;

            flag1 = ;

        }

    }

    if (flag1 == )

        cout << "None!\n";

    cout << "Potrons\n";

    for (int i = ; i < num; ++i)

    {

        if (!(potrons[i].money > ))

        {

            cout << potrons[i].name << " : " << potrons[i].money << endl;

            flag2 = ;

        }

    }

    if (flag2 == )

        cout << "None!\n";

    system("pause");

}

#include <iostream>

#include <cctype>

using namespace std;

const int MAX = ;

int main()

{

    char words[MAX][];

    char ch;

    int num_y = , num_f = , num_o = ;

    cout << "Enter words (q to quit):\n";

    for (int i = ; i < MAX; ++i)

    {

        cin >> words[i];

        ch = words[i][];

        if (ch == 'q')

            break;

        if (isalpha(ch))

        {

            switch (ch)

            {

            case 'a':;

            case 'e':;

            case 'i':;

            case 'o':;

            case 'u':

                num_y += ;

                break;

            default:

                num_f += ;

                break;

            }

        }

        else

            num_o += ;

    }

    cout << num_y << " beginning with vowels\n";

    cout << num_f << " beginning with consonants\n";

    cout << num_o << " others\n";

    system("pause");

}

#include <iostream>

#include <fstream>

#include <cstdlib>

using namespace std;

const int SIZE = ;

int 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.\n";

        exit(EXIT_FAILURE);

    }

    int count=;

    char ch;

    infile >> ch;

    while (infile.good())

    {

        ++count;

//        ch= infile.get();//读取空白字符

        infile >> ch;//不读取空白字符

    }

    cout << "The number of characters in the file is: " << count << endl;

    system("pause");

}

#include <iostream>

#include <string>

#include <fstream>

#include <cstdlib>

using namespace std;

const int SIZE = ;

struct potron

{

    string name;

    double money;

};

int 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.\n";

        exit(EXIT_FAILURE);

    }

    int num;

    infile >> num;

    potron *potrons = new potron[num];

    for (int i = ; i < num; ++i)

    {

        infile.ignore();

        getline(infile, potrons[i].name);

        infile >> potrons[i].money;

    }

    int flag1 = , flag2 = ;

    cout << "Grand Potrons\n";

    for (int i = ; i < num; ++i)

    {

        if (potrons[i].money > )

        {

            cout << potrons[i].name << " : " << potrons[i].money << endl;

            flag1 = ;

        }

    }

    if (flag1 == )

        cout << "None!\n";

    cout << "Potrons\n";

    for (int i = ; i < num; ++i)

    {

        if (!(potrons[i].money > ))

        {

            cout << potrons[i].name << " : " << potrons[i].money << endl;

            flag2 = ;

        }

    }

    if (flag2 == )

        cout << "None!\n";

    system("pause");

}