C++ Primer Plus第六版编程练习---第6章 分支语句和逻辑运算符

1、

#include <iostream>
#include <string>
#include <cctype>

int main()
{
    std::string inputStr;
    std::cout<<"Enter your character list. enter @ to end." << std::endl;
    char ch;
    std::string srcStr;
    std::string dstStr;
    while(std::cin.get(ch))
    {
        if(ch == '@')
        {
            std::cout << "input befor exchane: " << srcStr << std::endl;
            std::cout << "input after exchane: " << dstStr << std::endl;
            break;
        }
        srcStr = srcStr + ch;
        if(islower(ch))
        {
            dstStr = dstStr + char(toupper(ch));
            continue;   //必须有continue，否则全转为小写了
        }
        if(isupper(ch))
        {
            dstStr = dstStr + char(tolower(ch));
            continue;
        }
        dstStr = dstStr + ch;    //其他字符原样显示
    }
    return 0;
}

2、

#include <iostream>
#include <array>

int main()
{
    const int size = 10;
    std::array<double,size> donation;
    double sum = 0.0;
    double avrgValue = 0.0;
    int countLager = 0;
    int enterNum = 0;
    std::cout<<"Pleas enter up 10 double value, Non-digital to exit."<<std::endl;
    while((enterNum < size) && (std::cin>>donation[enterNum]))
    {
        sum += donation[enterNum];
        enterNum++;
    }
    avrgValue = sum/enterNum;
    for(int i=0; i<enterNum;i++)
    {
        if(donation[i] > avrgValue)
        {
            countLager++;
        }
    }

    std::cout<<"There have " << countLager << " larger than everage." << std::endl;

    return 0;
}

3、

#include <iostream>
#include <string>
 
 void useage()
 {
     std::cout<<"Please enter one of the following choices:"<<std::endl;
     std::cout<<"c) carnivore\t"<<"p) pianist"<<std::endl;
     std::cout<<"t) tree\t\t"<<"g) game"<<std::endl;
 }
 
 void tip()
 {
     std::cout<<"Please enter a c, p, t or g: ";
 }
 int main()
 {
     useage();
     char ch;
     while(true)
     {
         std::cin>>ch;
         switch(ch)
         {
         case 'c':
             std::cout<<"A tager is a carnivore." << std::endl;
             continue;
         case 'p':
             std::cout<<"Beethoven is a pianist." << std::endl;
             continue;
         case 't':
             std::cout<<"A maple is a tree." << std::endl;
             continue;
         case 'g':
             std::cout<<"Chess is a game." << std::endl;
             continue;
         default:
             tip();
             continue;
         }
     }
     return 0;
 }

 

 4、

#include <iostream>
#include <string>

#define strsize 100
//Benevolent Order of Programmers 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
};

void useage()
{
    std::cout<<"a) display by name\t"<<"b) display by title"<<std::endl;
    std::cout<<"c) display by bopname\t"<<"d) display by preference"<<std::endl;
    std::cout<<"q) quit"<<std::endl;
}

void nextChoice()
{
    std::cout<<"Next choice: ";
}

int main()
{
    bop userInfo[3]={{"Wimp Macho","title of Wimp Macho","bopname of Wimp Macho",0},
                    {"Raki Rhodes","title of Raki Rhodes","bopname of Raki Rhodes",1},
                    {"Celia Laiter","title of Celia Laiter","bopname of Celia Laiter",2},
    };
    useage();
    char ch;
    std::cout<<"Enter your choice:";
    while(true)
    {
        std::cin>>ch;
        if(ch != 'a' && ch != 'b' && ch != 'c' && ch != 'd' && ch != 'q')
        {
            std::cout<<"Enter your choice:";
            continue;
        }
        if(ch == 'a')
        {
            for(unsigned int i=0;i<3;i++)
            {
                std::cout<< userInfo[i].fullname << std::endl;
            }
            nextChoice();
            continue;
        }
        if(ch == 'b')
        {
            for(unsigned int i=0;i<3;i++)
            {
                std::cout<< userInfo[i].title << std::endl;
            }
            nextChoice();
            continue;
        }
        if(ch == 'c')
        {
            for(unsigned int i=0;i<3;i++)
            {
                std::cout<< userInfo[i].bopname << std::endl;
            }
            nextChoice();
            continue;
        }
        if(ch == 'd')
        {
            for(unsigned int i=0;i<3;i++)
            {
                if(userInfo[i].preference == 0)
                {
                    std::cout<< userInfo[i].fullname << std::endl;
                }
                else if(userInfo[i].preference == 1)
                {
                    std::cout<< userInfo[i].title << std::endl;
                }
                else if(userInfo[i].preference == 2)
                {
                    std::cout<< userInfo[i].bopname << std::endl;
                }
            }
            nextChoice();
            continue;
        }
        if(ch == 'q')
        {
            std::cout<<"Bye!" << std::endl;
            break;
        }
    }
    return 0;
}

5、

#include <iostream>
#include <string>

int main()
{
    double income = 0;
    std::cout<<"Please enter your income."<<std::endl;
    while(std::cin>>income)  //非数字的输入将使得cin方法调用返回false
    {
        if(income<0)
        {
            break;
        }
        if(income<=5000)
        {
            std::cout<<"Your income tax is: 0.00 tvarps." << std::endl;
        }
        else if(income<=15000)
        {
            std::cout<<"Your income tax is: " << 5000*0.00+(income-5000)*0.10 <<" tvarps."<< std::endl;
        }
        else if(income<=35000)
        {
            std::cout<<"Your income tax is: " << 5000*0.00+10000*0.10+(income-15000)*0.15 <<" tvarps."<< std::endl;
        }
        else
        {
            std::cout<<"Your income tax is: " << 5000*0.00+10000*0.10+20000*0.15+(income-35000)*0.20 <<" tvarps."<< std::endl;
        }
    }
    return 0;
}

6、

#include <iostream>
#include <string>

struct patron{
    std::string name;
    double amount;
};

int main()
{
    int countOfPatrons = 0;
    std::cout<<"Please enter count of patrons: ";
    std::cin>>countOfPatrons;
    std::cin.get();
    patron * pointPatrons = new patron[countOfPatrons];
    for(int i=0; i<countOfPatrons; i++)
    {
        std::cout<<"Please enter the name of patron."<<std::endl;
        getline(std::cin, pointPatrons[i].name);
        std::cout<<"Please enter the amount of patron."<<std::endl;
        std::cin>>pointPatrons[i].amount;
        std::cin.get();
    }
    std::cout<<"Grand Patrons"<<std::endl;
    for(int i=0; i<countOfPatrons; i++)     //有没有什么办法可以不使用这么多for循环
    {
        if(pointPatrons[i].amount > 10000)
        {
            if(pointPatrons[i].name.empty())
            {
                std::cout << "none\t"<<pointPatrons[i].amount<<std::endl;
            }
            std::cout << pointPatrons[i].name<<"\t"<<pointPatrons[i].amount<<std::endl;
        }
    }

    std::cout<<"Patrons"<<std::endl;
    for(int i=0; i<countOfPatrons; i++)
    {
        if(pointPatrons[i].amount <= 10000)
        {
            if(pointPatrons[i].name.empty())
            {
                std::cout << "none\t"<<pointPatrons[i].amount<<std::endl;
            }
            std::cout << pointPatrons[i].name<<"\t"<<pointPatrons[i].amount<<std::endl;
        }
    }
    delete[] pointPatrons;
    return 0;
}

7、

#include <iostream>
#include <string>
#include <cctype>

int main()
{
    char word[100]={'\0'};
    int wordsStartVow = 0;
    int wordsStartCons = 0;
    int otherCount = 0;
    std::cout<<"Enter words (q to quit):" <<std::endl;
    while(std::cin>>word)
    {
        bool quit = true;
        for(int i=0;word[i] != '\0';i++)
        {
            if(word[i] != 'q')
            {
                quit = false;
            }
        }
        if(quit)
        {
            break;
        }
        if(!isalpha(word[0]))
        {
            otherCount++;
            continue;
        }

        switch(word[0])
        {
        case 'a':
        case 'e':
        case 'i':
        case 'o':
        case 'u':
            wordsStartVow++;
            continue;
        default:
            wordsStartCons++;
        }
    }
    std::cout<<wordsStartVow<<" words beginning with vowels."<<std::endl;
    std::cout<<wordsStartCons<<" words beginning with consonants."<<std::endl;
    std::cout<<otherCount<<" others."<<std::endl;
    return 0;
}

8、

#include <iostream>
#include <fstream>

int main()
{
    std::ifstream file;
    file.open("E:\\test.txt");
    if(!file.is_open())
    {
        std::cout<<"Could not open the file E:\\test.txt"<<std::endl;
        return -1;
    }
    int countCharacter = 0;
    char ch;
    while(file.get(ch) && file.good())
    {
        countCharacter++;
        std::cout<<ch;
    }
    std::cout<<std::endl<<"file E:\\test.txt contain "<< countCharacter << " Characteres."<<std::endl;
    file.close();
    return 0;
}

9、

#include <iostream>
#include <string>
#include <fstream>

struct patron{
    char name[100];
    double amount;
};

int main()
{
    std::ifstream pfile;
    pfile.open("E:\\test.txt");
    int countOfPatrons = 0;
    pfile>>countOfPatrons;
    pfile.get();
    patron * pointPatrons = new patron[countOfPatrons];
    for(int i=0; i<countOfPatrons; i++)
    {
        pfile.getline(pointPatrons[i].name, 100);
        pfile>>pointPatrons[i].amount;
        pfile.get();
    }
    std::cout<<"Grand Patrons"<<std::endl;
    for(int i=0; i<countOfPatrons; i++)     //有没有什么办法可以不使用这么多for循环
    {
        if(pointPatrons[i].amount > 10000)
        {
            if(pointPatrons[i].name[0] == '\0')
            {
                std::cout << "none\t"<<pointPatrons[i].amount<<std::endl;
            }
            std::cout << pointPatrons[i].name<<"\t"<<pointPatrons[i].amount<<std::endl;
        }
    }

    std::cout<<"Patrons"<<std::endl;
    for(int i=0; i<countOfPatrons; i++)
    {
        if(pointPatrons[i].amount <= 10000)
        {
            if(pointPatrons[i].name[0] == '\0')
            {
                std::cout << "none\t"<<pointPatrons[i].amount<<std::endl;
            }
            std::cout << pointPatrons[i].name<<"\t"<<pointPatrons[i].amount<<std::endl;
        }
    }

    delete[] pointPatrons;
    pfile.close();
    return 0;
}