C++ Primer Plus 第六版第八章课后编程练习答案

╰半橙微兮° 2023-06-28 12:29 23阅读 0赞

#include <iostream>
    using namespace std;
    void print(char * str, int n=0);
    
    int main()
    {
        char str[30] = "I love u.";
        print(str);
        print(str, 1);
        print(str, 2);
        print(str);
    
        return 0;
    }
    
    void print(char * str, int n)
    {
        static int flag=0;//全局静态变量，再调用时会保持在更新后的值，而不是初始值
        flag++;
        if(n==0)
            cout << str << endl;
        else
        {
            for(int i=0; i<flag; i++)
                cout << str << endl;
        }
        cout << endl;
    }

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#include <iostream>
    using namespace std;
    
    struct CandyBar
    {
        string brand;
        double weight;
        int heat;
    };
    
    void set(CandyBar & x, const char * brand="Millennium Munch", const double weight=2.85, const int heat=350);
    void show(CandyBar & x);
    
    
    int main()
    {
        CandyBar x0, x1, x2;
        set(x0);
        show(x0);
    
        set(x1, "AA", 1.11, 100);
        show(x1);
    
        set(x2, "BB", 2.22, 200);
        show(x2);
    
        return 0;
    }
    
    void set(CandyBar & x, const char * brand, const double weight, const int heat)
    {
        x.brand = brand;
        x.weight = weight;
        x.heat = heat;
    }
    
    void show(CandyBar & x)
    {
        cout << "Brand: " << x.brand << endl;
        cout << "Weight: " << x.weight << endl;
        cout << "Heat: " << x.heat << endl;
    }

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#include <iostream>
    #include <cctype>
    using namespace std;
    string ToUper(string & x);
    
    int main()
    {
        cout << "Enter a string (q to quit): ";
        string str;
        getline(cin, str);//不能cin>>str
        while (str != "q")
        {
            str = ToUper(str);
            cout << str << endl;
            cout << "Next string (q to quit): ";
            getline(cin, str);
        }
        cout << "Bye." << endl;
    
        return 0;
    }
    
    string ToUper(string & x)
    {
        for(int i=0; x[i]; i++)
            x[i] = toupper(x[i]);
        return x;
    }

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4.暂

#include <iostream>
    using namespace std;
    template<typename T>
    T max5(T x[5]);
    
    int main()
    {
        int x[5] = {2, 4, 6, 8, 10};
        double y[5] = {2.2, 4.4, 6.6, 8.8, 9.9};
        int max_x;
        double max_y;
        max_x = max5(x);
        max_y = max5(y);
        cout << "Int array: " << x[0] << ", " << x[1] << ", " << x[2] << ", " << x[3] << ", " << x[4] << endl;
        cout << "Biggest num: " << max_x << endl;
        cout << "Double array: " << y[0] << ", " << y[1] << ", " << y[2] << ", " << y[3] << ", " << y[4] << endl;
        cout << "Biggest num: " << max_y << endl;
    
        return 0;
    }
    
    template<typename T> //T类型
    T max5(T x[5])
    {
        T max;
        max = x[1] > x[0] ? x[1]:x[0];
        max = x[2] > max ? x[2]:max;
        max = x[3] > max ? x[3]:max;
        max = x[4] > max ? x[4]:max;
        return max;
    }

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#include <iostream>
    using namespace std;
    template <typename T>
    T maxn(T arr[], int n);
    char * max_n(char * arr[], int n);
    
    int main()
    {
        int arr1[6] = {1, 2, 3, 4, 5, 6};
        double arr2[4] = {1.1, 2.2, 3.3, 4.4};
        char * arr3[5] = {"a", "bbb", "cc", "dddd", "e"};
        int max1;
        double max2;
        char * max3;
        max1 = maxn(arr1, 6);
        max2 = maxn(arr2, 4);
        max3 = max_n(arr3, 5);
        cout << "Biggest num of arr1: " << max1 << endl;
        cout << "Biggest num of arr2: " << max2 << endl;
        cout << "Longest address of arr3: " << &max3 << endl;
    
        return 0;
    }
    
    template <typename T>
    T maxn(T arr[], int n)
    {
        T max=0;
        for(int i=0; i<n; i++)
            max = arr[i]>max ? arr[i]:max;
        return max;
    }
    
    char * max_n(char * arr[], int n) //返回地址
    {
        int max_len = 0;
        int j = 0;
        char * address;
        for(int i=0; i<n; i++)
        {
            if(strlen(arr[i]) > max_len)
            {
                max_len = strlen(arr[i]);
                j = i;
            }
        }
        address = arr[j];//字符串地址中最长的那个
        return address;
    }

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//原程序是2个传参及传指针的用来显示的函数ShowArray，现改成2个求和的函数SumArray()
    #include <iostream>
    using namespace std;
    template <typename T>
    T SumArray(T arr[], int n);
    template <typename T>
    T SumArray(T * arr[], int n);
    
    struct debts
    {
        char name[50];
        double amount;
    };
    
    int main()
    {
        int things[6] = {13, 31, 103, 301, 310, 130};
        debts mr_E[3] =
                {
                        {"Ima Wolfe", 2400.0},
                        {"Ura Foxe", 1300.0},
                        {"Iby Stout", 1800.0}
                };
        double * pd[3];
        for(int i=0; i<3; i++)
            pd[i] = &mr_E[i].amount;
    
        int sum1 = SumArray(things, 6);
        cout << "The sum of things is " << sum1 << endl;
        double sum2 = SumArray(pd, 3);
        cout << "The sum of Mr.E's debts is " << sum2 << endl;
    
        return 0;
    }
    
    template <typename T>
    T SumArray(T arr[], int n)
    {
        T sum=0;
        cout << "template A\n";
        for(int i=0; i<n; i++)
            sum += arr[i];
        return sum;
    }
    
    template <typename T>
    T SumArray(T * arr[], int n)
    {
        T sum=0;
        cout << "template B\n";
        for(int i=0; i<n; i++)
            sum += *arr[i];
        return sum;
    }

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