C++ Primer Plus 第六版第十七章课后编程练习答案

淡淡的烟草味﹌ 2023-05-22 08:47 10阅读 0赞

play.cpp

#include <iostream>
    using namespace std;
    
    int main()
    {
        cout << "Enter input: \n";
        int count = 0;
        char ch;
        //题目要求将$留在输入流中, 用cin.get()函数来获取字符，这样停止获取的最后一个字符会留在输入流中
        cin.get(ch);
        while (ch != '$' && ch != '\n')
        {
            count ++;
            cin.get(ch);
        }
        if(ch == '$')
            cout << " $ has been deleted.\n ";
        else
            cout << "Input finished.\n";
        cout << "Total count: " << count << endl;
    
        return 0;
    }

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzM5OTM4NjY2_size_16_color_FFFFFF_t_70][]

play.cpp

#include <iostream>
    using namespace std;
    #include <cstdlib>
    #include <fstream>
    #include <string>
    
    int main(int argc, char * argv[])
    {
        ofstream fout;
        for(int i = 1; i < argc; i++)
        {
            fout.open(argv[i]);
            if(! fout.is_open())
            {
                cerr << "Can't open " << argv[i] << endl;
                exit(EXIT_FAILURE);
            }
            cout << "Enter input(enter blank line to quit): \n";
            string input;
            while (getline(cin, input) && input.size() > 0)
                fout << input << endl;
            cout << "Input finished.\n";
            fout.close();
        }
    
        return 0;
    }

play.cpp

#include <iostream>
    using namespace std;
    #include <cstdlib>
    #include <fstream>
    #include <string>
    
    int main(int argc, char * argv[])
    {
        ifstream  fin;
        ofstream fout;
        char ch;
        fin.open(argv[1]);
        fout.open(argv[2]);
        if(! fin.is_open())
        {
            cerr << "Can't open " << argv[1] << endl;
            fin.clear();
            exit(EXIT_FAILURE);
        }
        if(! fout.is_open())
        {
            cerr << "Can't open " << argv[2] << endl;
            fout.close();
            exit(EXIT_FAILURE);
        }
        cout << "Open successfully.\n";
        cout << "Now begin to copy and paste.\n";
        while (fin.get(ch))
            fout << ch;
        fin.clear();
        fin.close();
        fout.close();
        cout << "Copy and paste successfully.\n";
    
        return 0;
    }

play.cpp

#include <iostream>
    using namespace std;
    #include <cstdlib>
    #include <fstream>
    #include <string>
    
    int main(int argc, char * argv[])
    {
        ifstream fin1, fin2;
        ofstream fout;
        fin1.open("input1.txt");
        fin2.open("input2.txt");
        fout.open("output.txt");
        if(! fin1.is_open())
        {
            cerr << "Can't open input1.txt \n";
            fin1.clear();
            fin2.clear();
            fout.close();
            exit(EXIT_FAILURE);
        }
        if(! fin2.is_open())
        {
            cerr << "Can't open input2.txt \n";
            fin1.clear();
            fin2.clear();
            fout.close();
            exit(EXIT_FAILURE);
        }
        if(! fout.is_open())
        {
            cerr << "Can't open output.txt \n";
            fin1.clear();
            fin2.clear();
            fout.close();
            exit(EXIT_FAILURE);
        }
        cout << "Open successfully.\n";
        cout << "Begin to read and write.\n";
        string input1;
        string input2;
        int count1 = 0, count2 = 0, total_count;
        while (getline(fin1, input1))
            count1++;
        while (getline(fin2, input2))
            count2++;
        total_count = (count1 >= count2 ? count2 : count1);//取小
    
        //先使用两个输入流打开文件，使用getline()函数读一遍之后获取两个文件的行数，
        // 关闭文件之后又重新使用输入流再打开，进行数据的复制，此时因为第一遍读取的时候已经获取了行数，所以可以直接复制。
        fin1.clear();
        fin2.clear();
        fin1.close();
        fin2.close();
        fin1.open("input1.txt");
        fin2.open("input2.txt");
        if(! fin1.is_open())
        {
            cerr << "Can't open input1.txt \n";
            fin1.clear();
            fin2.clear();
            fout.close();
            exit(EXIT_FAILURE);
        }
        if(! fin2.is_open())
        {
            cerr << "Can't open input2.txt \n";
            fin1.clear();
            fin2.clear();
            fout.close();
            exit(EXIT_FAILURE);
        }
        for(int i = 0; i < total_count; i++)
        {
            getline(fin1, input1);
            getline(fin2, input2);
            fout << input1 << " " << input2 << endl;
        }
        if(count1 >= count2)
        {
            for(int i = total_count; i < count1; i++)
            {
                getline(fin1, input1);
                fout << input1 << endl;
            }
        }
        else
        {
            for(int i = total_count; i < count2; i++)
            {
                getline(fin2, input2);
                fout << input2 << endl;
            }
        }
        cout << "Finished.\n";
    
        return 0;
    }

play.cpp

#include <iostream>
    using namespace std;
    #include <cstdlib>
    #include <fstream>
    #include <string>
    #include <set>
    #include <iterator>
    
    int main()
    {
        ifstream fin1, fin2;
        ofstream fout;
        fin1.open("mat.dat");
        fin2.open("pat.dat");
        fout.open("matnpat.dat");
        if(! fin1.is_open())
        {
            cerr << "Can't open mat.dat \n";
            exit(EXIT_FAILURE);
        }
        if(! fin2.is_open())
        {
            cerr << "Can't open pat.dat \n";
            exit(EXIT_FAILURE);
        }
        if(! fout.is_open())
        {
            cerr << "Can't open matnpat.dat \n";
            exit(EXIT_FAILURE);
        }
        string temp;
        set<string> mat, pat, matnpat;
        while (getline(fin1, temp))
            mat.insert(temp);
        ostream_iterator<string, char> output(cout, "\n");
        cout << "Mat's friends:\n";
        copy(mat.begin(), mat.end(), output);
        while (getline(fin2, temp))
            pat.insert(temp);
        cout << "Pat's friends:\n";
        copy(pat.begin(), pat.end(), output);
        ostream_iterator<string, char> out(fout, "\n");
        set_union(mat.begin(), mat.end(), pat.begin(), pat.end(),
                insert_iterator<set<string>>(matnpat, matnpat.begin()));
        cout << "Total friends: \n";
        copy(matnpat.begin(), matnpat.end(), output);
        copy(matnpat.begin(), matnpat.end(), out);
    
        return 0;
    }

emp.h

#ifndef EMP_H
    #define EMP_H
    #include <iostream>
    #include <string>
    #include <fstream>
    using namespace std;
    enum classkind{Zero, Employee, Manager, Fink, HighFink};
    class abstr_emp
    {
        string fname;
        string lname;
        string job;
    public:
        abstr_emp();
        abstr_emp(const string &fn, const string &ln, const string &j);
        virtual void ShowAll() const ;
        virtual void SetAll();
        virtual void setall(ifstream &fin);
        virtual void writeall(ofstream &fout);
        friend ostream &operator<<(ostream &os, const abstr_emp &e);
        virtual ~abstr_emp() = 0;
    };
    
    class employee : public abstr_emp
    {
    public:
        employee();
        employee(const string &fn, const string &ln, const string &j);
        virtual void ShowAll() const ;
        virtual void SetAll();
        virtual void setall(ifstream &fin);
        virtual void writeall(ofstream &fout);
    };
    
    class manager : virtual public abstr_emp
    {
        int inchargeof;
    protected:
        int InChargeOf() const { return inchargeof;}
        int & InChargeOf() { return inchargeof;}
    public:
        manager();
        manager(const string &fn, const string &ln, const string &j, int ico = 0);
        manager(const abstr_emp &e, int ico);
        manager(const manager &m);
        virtual void ShowAll() const ;
        virtual void SetAll();
        virtual void setall(ifstream &fin);
        virtual void writeall(ofstream &fout);
    };
    
    class fink : virtual public abstr_emp
    {
        string reportsto;
    protected:
        const string ReportsTo() const { return reportsto;}
        string &ReportsTo() { return reportsto;}
    public:
        fink();
        fink(const string &fn, const string &ln, const string &j, const string &rpo);
        fink(const abstr_emp &e, const string &rpo);
        fink(const fink &e);
        virtual void ShowAll() const ;
        virtual void SetAll();
        virtual void setall(ifstream &fin);
        virtual void writeall(ofstream &fout);
    
    };
    
    class highfink : public manager, public fink
    {
    public:
        highfink();
        highfink(const string &fn, const string &ln, const string &j, const string &rpo, int ico);
        highfink(const abstr_emp &e, const string &rpo, int ico);
        highfink(const fink &f, int ico);
        highfink(const manager &m, const string &rpo);
        highfink(const highfink &h);
        virtual void ShowAll() const ;
        virtual void SetAll();
        virtual void setall(ifstream &fin);
        virtual void writeall(ofstream &fout);
    };
    
    #endif

emp.cpp

#include "emp.h"
    #include <iostream>
    using namespace std;
    #include <fstream>
    #include <string>
    
    abstr_emp::abstr_emp()
    {
        fname = "None";
        lname = "None";
        job = "None";
    }
    
    abstr_emp::abstr_emp(const string &fn, const string &ln, const string &j)
    {
        fname = fn;
        lname = ln;
        job = j;
    }
    
    void abstr_emp::ShowAll() const
    {
        cout << "First name: " << fname << endl;
        cout << "Last name: " << lname << endl;
        cout << "Job: " << job << endl;
    }
    
    void abstr_emp::SetAll()
    {
        cout << "Enter firstname: ";
        getline(cin, fname);
        cout << "Enter lastname: ";
        getline(cin, lname);
        cout << "Enter job: ";
        getline(cin, job);
    }
    
    void abstr_emp::setall(ifstream & fin)
    {
        getline(fin, fname);
        getline(fin, lname);
        getline(fin, job);
    }
    
    void abstr_emp::writeall(ofstream & fout)
    {
        fout << fname << endl << lname << endl << job << endl;
    }
    
    ostream &operator<<(ostream &os, const abstr_emp &e)
    {
        os << endl;
        os << "Firstname: " << e.fname << endl;
        os << "Lastname: " << e.lname << endl;
        return os;
    }
    
    abstr_emp::~abstr_emp() {}
    
    employee::employee()
    :  abstr_emp()
    {}
    
    employee::employee(const string &fn, const string &ln, const string &j)
    : abstr_emp(fn, ln, j)
    {}
    
    void employee::ShowAll() const
    {
        cout << "\nEmployee: " << endl;
        abstr_emp::ShowAll();
    }
    
    void employee::SetAll()
    {
        cout << "Employee: " << endl;
        abstr_emp::SetAll();
    }
    
    void employee::setall(ifstream & fin)
    {
        abstr_emp::setall(fin);
    }
    
    void employee::writeall(ofstream & fout)
    {
        fout << Employee << endl;
        abstr_emp::writeall(fout);
    }
    
    manager::manager()
    : abstr_emp()
    {}
    
    manager::manager(const string &fn, const string &ln, const string &j, int ico)
    : abstr_emp(fn, ln, j), inchargeof(ico)
    {}
    
    manager::manager(const abstr_emp &e, int ico)
    : abstr_emp(e), inchargeof(ico)
    {}
    
    manager::manager(const manager &m)
    : abstr_emp(m)
    {
        inchargeof = m.inchargeof;
    }
    
    void manager::ShowAll() const
    {
        cout << "\nManager: " << endl;
        abstr_emp::ShowAll();
        cout << "In charge of " << inchargeof << " employees.\n";
    }
    
    void manager::SetAll()
    {
        cout << "Manager: " << endl;
        abstr_emp::SetAll();
        cout << "In charge of: ";
        cin >> inchargeof;
        cin.ignore();
    }
    
    void manager::setall(ifstream & fin)
    {
        abstr_emp::setall(fin);
        fin >> inchargeof;
        fin.ignore();
    }
    
    void manager::writeall(ofstream & fout)
    {
        fout << Manager << endl;
        abstr_emp::writeall(fout);
        fout << inchargeof << endl;
    }
    
    fink::fink()
    : abstr_emp()
    {
        reportsto = "None";
    }
    
    fink::fink(const string &fn, const string &ln, const string &j, const string &rpo)
    : abstr_emp(fn, ln, j), reportsto(rpo)
    {}
    
    fink::fink(const abstr_emp &e, const string &rpo)
    : abstr_emp(e), reportsto(rpo)
    {}
    
    fink::fink(const fink &f)
    : abstr_emp(f)
    {
        reportsto = f.reportsto;
    }
    
    void fink::ShowAll() const
    {
        cout << "\nFink: " << endl;
        abstr_emp::ShowAll();
        cout << "Reports to: " << reportsto << endl;
    }
    
    void fink::SetAll()
    {
        cout << "Fink: " << endl;
        abstr_emp::SetAll();
        cout << "Reports to: " ;
        getline(cin, reportsto);
    }
    
    void fink::setall(ifstream & fin)
    {
        abstr_emp::setall(fin);
        fin >> reportsto;
        fin.ignore();
    }
    
    void fink::writeall(ofstream & fout)
    {
        fout << Fink << endl;
        abstr_emp::writeall(fout);
        fout << reportsto << endl;
    }
    
    highfink::highfink()
    : abstr_emp(), manager(), fink()
    {}
    
    highfink::highfink(const string &fn, const string &ln, const string &j, const string &rpo, int ico)
    : abstr_emp(fn, ln, j), manager(fn, ln, j, ico), fink(fn, ln, j, rpo)
    {}
    
    highfink::highfink(const abstr_emp &e, const string &rpo, int ico)
    : abstr_emp(e), manager(e, ico), fink(e, rpo)
    {}
    
    highfink::highfink(const fink &f, int ico)
    : abstr_emp(f), manager(f, ico), fink(f)
    {}
    
    highfink::highfink(const manager &m, const string &rpo)
    : abstr_emp(m), manager(m), fink(m, rpo)
    {}
    
    highfink::highfink(const highfink &h)
    : abstr_emp(h), manager(h), fink(h)
    {}
    
    void highfink::ShowAll() const
    {
        cout << endl;
        cout << "Highfink: " << endl;
        abstr_emp::ShowAll();
        cout << "In charge of: " << manager::InChargeOf() << endl;
        cout << "Reports to: " << fink::ReportsTo() << endl;
        cout << endl;
    }
    
    void highfink::SetAll()
    {
        cout << "Highfink: " << endl;
        abstr_emp::SetAll();
        cout << "In charge of: " ;
        cin >> manager::InChargeOf();
        cout << "Reports to: ";
        getline(cin, fink::ReportsTo());
    }
    
    void highfink::setall(ifstream & fin)
    {
        abstr_emp::setall(fin);
        fin >> manager::InChargeOf();
        fin.ignore();
        fin >> fink::ReportsTo();
        fin.ignore();
    }
    
    void highfink::writeall(std::__1::ofstream & fout)
    {
        fout << HighFink << endl;
        abstr_emp::writeall(fout);
        fout << manager::InChargeOf() << endl;
        fout << fink::ReportsTo() << endl;
    }

play.cpp

#include <iostream>
    #include <fstream>
    #include <cstdlib>
    #include <string>
    #include "emp.h"
    
    const int MAX = 10;
    const char * file = "staff.txt";
    
    int main()
    {
        using namespace std;
        abstr_emp *pc[MAX];
    
        //打开文件并读取
        ifstream fin;
        int classtype;
        int i = 0;
        char ch;
        fin.open(file);
        if (fin.is_open())
        {
            cout << "Here are the current contents of the " << file << " file:\n";
            while ((fin >> classtype).get(ch))
            {
                switch (classtype)
                {
                    case Employee: pc[i] = new employee; break;
                    case Manager: pc[i] = new manager; break;
                    case Fink: pc[i] = new fink; break;
                    case HighFink: pc[i] = new highfink; break;
                    default: cerr << "Warning: Type error!\n"; break;
                }
                pc[i]->setall(fin);
                pc[i]->ShowAll();
                i++;
            }
            fin.close();
        }
    
        //添加新内容
        ofstream fout(file, ios::out | ios::app);  //打开写入，只追加
        if (!fout.is_open())
        {
            cerr << "Can't open " << file << " file for output.\n";
            system("pause");
            exit(EXIT_FAILURE);
        }
        int index = 0;
        cout << "\nPlease enter the class type of your input:\n";
        cout << "1)Employee\t2)Manager\t3)Fink\t\t4)Highfink\tq)Quit\n";
        while (cin >> classtype && index < MAX)
        {
            cin.ignore();
            switch (classtype)
            {
                case 1:
                    pc[index] = new employee;
                    pc[index]->SetAll();
                    break;
                case 2:
                    pc[index] = new manager;
                    pc[index]->SetAll();
                    break;
                case 3:
                    pc[index] = new fink;
                    pc[index]->SetAll();
                    break;
                case 4:
                    pc[index] = new highfink;
                    pc[index]->SetAll();
                    break;
                default:
                    cerr << "Warning: Type error!\n";
                    break;
            }
            index++;
            cout << "\nPlease enter the class type of your input:\n";
            cout << "1)Employee\t2)Manager\t3)Fink\t\t4)Highfink\tq)Quit\n";
        }
        cout << "Input over.\nThank You!\n";
        cout << "Begin to write into the file...\n";
        cout << "Writing...\n";
        for (i = 0; i < index; i++)
            pc[i]->writeall(fout);
        fout.close();
        cout << "Write over.\n";
    
        //显示所有数据
        fin.clear();
        fin.open(file);
        if (fin.is_open())
        {
            cout << "Here are the current contents of the " << file << " file:\n";
            while ((fin >> classtype).get(ch))
            {
                switch (classtype)
                {
                    case Employee: pc[i] = new employee; break;
                    case Manager: pc[i] = new manager; break;
                    case Fink: pc[i] = new fink; break;
                    case HighFink: pc[i] = new highfink; break;
                    default: cerr << "Warning: Type error!\n"; break;
                }
                pc[i]->setall(fin);
                pc[i]->ShowAll();
                i++;
            }
            fin.close();
        }
    
        system("pause");
        return 0;
    }

play.cpp

#include <iostream>
    using namespace std;
    #include <cstdlib>
    #include <algorithm>
    #include <fstream>
    #include <vector>
    #include <string>
    
    void ShowStr(const string &str);
    void GetStrs(istream &is, vector<string> &vstr);
    
    class Store
    {
    public:
        ostream &os;
        Store(ostream &o) : os(o) {}
        void operator() (const string &str);
    };
    
    void Store::operator()(const string & str)
    {
        size_t len = str.size();
        os.write((char*)&len, sizeof(size_t));
        os.write(str.data(), len);
    }
    
    int main()
    {
        vector<string> vostr;
        string temp;
    
        cout << "Enter string(empty line to quit): \n";
        while (getline(cin, temp) && temp[0] != '\0')
            vostr.push_back(temp);
        cout << "Here is your input.\n";
        for_each(vostr.begin(), vostr.end(), ShowStr);
    
        ofstream fout("strings.dat", ios_base::out | ios_base::binary);
        for_each(vostr.begin(), vostr.end(), Store(fout));
        fout.close();
    
        vector<string> vistr;
        ifstream fin("strings.dat", ios_base::in | ios_base::binary);
        if(! fin.is_open())
        {
            cerr << "Can't open.\n";
            exit(EXIT_FAILURE);
        }
        GetStrs(fin, vistr);
        cout << "Here are the strings read from the file:\n";
        for_each(vistr.begin(), vistr.end(), ShowStr);
    
        return 0;
    }
    
    void ShowStr(const string &str)
    {
        cout << str << endl;
    }
    
    void GetStrs(istream &is, vector<string> &vstr)
    {
        string temp;
        size_t len;
        while (is.read((char *)&len, sizeof(size_t)) && len > 0)
        {
            char ch;
            temp = "";
            for(int i = 0; i < len; i++)
            {
                if(is.read(&ch, 1))
                    temp += ch;
                else
                    break;
            }
            if(is)
                vstr.push_back(temp);
        }
    }

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