C++ Primer Plus（6th）第五章 编程练习题答案

1.输入两个整数，然后求之间数的和

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
	int num1;
	int num2;
	int i;
	int sum=0;
	cout<<"Please enter the first number:";
	cin>>num1;
	cout<<"Please enter the second number:";
	cin>>num2;
	for(i=num1;i<=num2;i++)
	{
		sum+=i;
	}
	cout<<"The sum of number "<<num1<<" to "<<num2<<",sum= "<<sum<<endl;
	return 0;
}

2.重新5.4

#include "stdafx.h"
#include<iostream>
#include<string>
#include<array>

using namespace std;

const int ArSize =16;

int main()
{
	array<long double, ArSize+1> factorials;
    factorials[0]=factorials[1]=1.0;
    for(int i=2;i<= ArSize;i++)
    {
        factorials[i]=i*factorials[i-1];
    }
    for (int i = 0; i <= ArSize; i++)
    {
        cout<<i<< "! = "<<factorials[i]<<endl;
    }
	return 0;
}

3.求累计和

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
	int num;
	int sum=0;
	while(1)
	{
		cout<<"Enter a number(0 to exit):";
		cin>>num;
		if(num==0)
		{
			break;
		}
		sum+=num;
		cout<<"Until now,the sum of the number you input ="<<sum<<endl;
	}
	cout<<"Ending!"<<endl;
	return 0;
}

4.投资比较

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
	double D_account=100;
	double C_account=100;
	int years=0;

	while(D_account>=C_account)
	{
		C_account+=C_account*0.05;
		D_account+=10;
		years++;
	}
	cout<<"After "<<years<<" years."<<"Cleo account ("<<C_account
		<<") will more than Daphne account ("<<D_account<<");"<<endl;
	return 0;
}

5.书一年中每月销售量

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
	string month[12] = { "January", "February", "March", "April", "May", "June", "July", 
                         "August", "Septempber", "October", "November", "December" };
    int sell[12];
    int total_sales = 0;

    cout<<"Enter the sales of book <C++ for Fools> each month: " << endl;
    for(int i = 0; i < 12; i++)
    {
        cout<<month[i]<<":";
        cin>>sell[i];
        total_sales+=sell[i];
    }

    cout<<"The total sales = "<<total_sales<<endl;
    cout<<"The sales of every month as following:"<<endl;
    for (int i=0; i<12;i++)
    {
        cout<<month[i]<<": "<<sell[i]<<endl;
    }
	return 0;
}

6.书三年中每月销量

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
	string month[12]={ "January", "February", "March", "April", "May", "June", "July", 
                       "August", "Septempber", "October", "November", "December" };
	string years[3]={"first","second","third"};
    unsigned int sales[3][12]={ 0 };
    unsigned int total_sales[3]={ 0 };

    for (int i = 0; i < 3; i++)
    {
        cout<<"Enter "<<years[i]<<" year sales of book <C++ for Fools> each month: "
            <<endl;
        for (int j=0; j<12;j++)
        {
            cout<<month[j]<< ": ";
            cin >>sales[i][j];
            total_sales[i]+=sales[i][j];
        }
    }

    for (int i=0;i<3;i++)
    {
        cout<<years[i]<<" year total sales is "<<total_sales[i]<<endl;
    }

    cout<<"Three years total sales is "<<total_sales[0]+total_sales[1]+total_sales[2]
        <<endl;

	return 0;
}

7.汽车信息

 

#include "stdafx.h"
#include<iostream>
#include<string>


using namespace std;

struct car
{
	string company;
	int pyear;
};

int main()
{
    int size = 0;
    cout << "How many cars do you wish to catalog? ";
    cin >>size;
    cin.get();

    struct car *pcar = new struct car[size];
    for (unsigned int i = 0; i < size; i++)
    {
        cout << "Car #" << i + 1 << ":" << endl;
        cout << "Please enter the make: ";
        getline(cin, pcar[i].company);

        cout << "Please enter the year make: ";
        cin >> pcar[i].pyear;
        cin.get();
    }

    cout << "Here is your collection:" << endl;
    for (int i = 0; i < size; i++)
    {
        cout << pcar[i].pyear << " " << pcar[i].company << endl;
    }
	return 0;
}

8.读取单词个数

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
    unsigned int n_word = 0;
    char input[128];

    cout << "Enter words (to stop, type the word done):" << endl;
    while (cin >> input)
    {
        if (strcmp(input, "done"))
        {
            n_word++;
        }
        else
        {
            break;
        }
    }

    cout << "You entered a total of " << n_word << " words." << endl;
    return 0;
}

9.改写8

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
    unsigned int n_word = 0;
    string input;

    cout << "Enter words (to stop, type the word done):" << endl;
    while (cin >> input)
    {
        if (input != "done")
        {
            n_word++;
        }
        else
        {
            break;
        }
    }

    cout << "You entered a total of " << n_word << " words." << endl;

    return 0;
}

10.嵌套程序

#include "stdafx.h"
#include<iostream>
#include<string>

using namespace std;

int main()
{
    int row = 0;

    cout<<"Enter number of rows: ";
    cin>>row;

    for(int i=1;i<=row;i++)
    {
        for(int j=i;j<row;j++)
        {
            cout<<".";
        }
        for(int j=0;j<i;j++)
        {
            cout<<"*";
        }
        cout<<endl;
    }

    return 0;
}