C++ Primer Plus 中文第六版 第四章编程练习答案

#include <iostream>
#include <string>
#include <array>

using namespace std;

void p4t1()
{
    char a0[20];
    char a1[20];
    char a2;
    int age=0;
    cout<<"What is your first name?"<<endl;
    cin>>a0;
    cout<<"What is your last name?"<<endl;
    cin>>a1;
    cout<<"What letter grade do you deserve?"<<endl;
    cin>>a2;
    a2+=1;
    cout<<"What is your age?"<<endl;
    cin>>age;
    cout<<"Name: "<<a1<<" "<<a0<<endl;
    cout<<"Grade: "<<a2;
    cout<<"Age: "<<age;
}

void p4t2()
{
    string name;
    string dessert;
    cout << "Enter your name:"<<endl;
    cin>>name;
    cout << "Enter your favourite dessert:"<<endl;
    cin>>dessert;
    cout << "I have some delicious " << dessert<< " for you, " << name << ".\n";;
}

void p4t3()
{
    char first_name[256];
    char last_name[256];
    cout <<"Enter your first name: "<<endl;
    cin.getline(first_name,256);
    cout <<"Enter your last name: "<<endl;
    cin.getline(last_name,256);
    cout << "Here's your infomation is a single string: "<<last_name<<","<<first_name<<endl;
}

void p4t4()
{
    string first_name;
    string last_name;
    cout <<"Enter your first name: "<<endl;
    getline(cin,first_name);
    cout <<"Enter your last name: "<<endl;
    getline(cin,last_name);
    cout << "Here's your infomation is a single string: "<<last_name<<","<<first_name<<endl;
}

struct CandyBar
{
    char name[256];
    float weight;
    int calory;
};
void p4t5()
{
    struct CandyBar snack={ "Mocha Munch", 2.3, 350 };
    cout<<"Name: "<<snack.name<<" : "<<snack.weight<<" : "<<" : "<<snack.calory<<endl;
}


void p4t6()
{
    struct CandyBar cs[3]={
        {"hello",7,7},{"bye",7,7},{"zip",7,7}
    };
    for (int i = 0; i < 3; i++) {
        cout << cs[i].calory <<" : "<< cs[i].weight <<" : "<< cs[i].name << endl;
    }
}

typedef struct pizza7{
    string name;
    double d;
    double weight;
}p7;

void p4t7()
{
        p7 newpizza;
        cout<<"INPUT PIZZA NAME"<<endl;
        getline(cin,newpizza.name);
        cout<<"INPUT PIZZA SIZE"<<endl;
        cin>>newpizza.d;
        cout<<"INPUT PIZZA WEIGHT"<<endl;
        cin>>newpizza.weight;

        cout<<newpizza.name<<newpizza.d<<newpizza.weight<<endl;
}

void p4t8()
{
    auto * pointer=new pizza7;
    cout<<"INPUT PIZZA SIZE"<<endl;
    cin>>pointer->d;
    cin.get();//这里是把缓冲区读走
    cout<<"INPUT PIZZA NAME"<<endl;
    getline(cin,pointer->name);
    cout<<"INPUT PIZZA WEIGHT"<<endl;
    cin>>pointer->weight;

    cout<<pointer->name<<pointer->d<<pointer->weight<<endl;
}

void p4t9()
{
    auto p=new struct CandyBar[3]{
            {"hello",7,7},{"bye",7,7},{"zip",7,7}
    };
    for (int i = 0; i < 3; i++) {
        cout << p[i].calory <<" : "<< p[i].weight <<" : "<< p[i].name << endl;
    }
}

void p4t10()
{
    array<float,3> a={0,0,0};
    cout<<"INPUT THREE GRADES"<<endl;
    cin>>a[0];
    cin>>a[1];
    cin>>a[2];
    cout<<a[0]<<"  "<<a[1]<<"  "<<a[2]<<"  "<<"AVERAGE:"<<(a[0]+a[1]+a[2])/3<<endl;

}
int main()
{
    while(1) {
        int num;
        cout << "\n输入要做的题号" << endl;
        cin >> num;
        if (num == 1)
            p4t1();
        else if(num==2)
            p4t2();
        else if(num==3)
            p4t3();
        else if(num==4)
            p4t4();
        else if(num==5)
            p4t5();
        else if(num==6)
            p4t6();
        else if(num==7)
            p4t7();
        else if(num==8)
            p4t8();
        else if(num==9)
            p4t9();
        else if(num==10)
            p4t10();
        else
            break;
    }
}