C++ Primer Plus第六版编程练习---第5章 循环和关系表达式

1、

#include <iostream>

int main()
{
    int startNum = 0;
    int endNum = 0;
    std::cout << "please enter tow num:" << std::endl;
    std::cin >> startNum;
    std::cin >> endNum;

    long long sum = 0;
    for(int i = startNum; i <= endNum; i++)
        sum += i;

    std::cout << "the sum betwen " << startNum << " and " << endNum << "is: " << sum << std::endl;
    return 0;
}

 2、

#include <iostream>
#include <array>
const int ArSize = 100;
 
int main()
{
    std::array<long double, ArSize> factorials;
    factorials[1] = factorials[0] = 1;
    for( int i = 2; i< ArSize; i++)
    {
        factorials[i] = i * factorials[i-1];
    }

    std::cout << "100! is : " << factorials[99] << std::endl;
    return 0;
}

3、

#include <iostream>
 
int main()
{
    long double sum = 0;
    int tempInput = 0;
    std::cin >> tempInput;
    while(tempInput != 0)
    {
        sum += tempInput;
        std::cin >> tempInput;
    }
    std::cout << "sum of all Numbers is : " << sum << std::endl;
    return 0;
}

4、

#include <iostream>
 
int main()
{
    long double investmentOfDaphne = 100;
    long double investmentOfCleo = 100;
    int yeas = 0;
    while(investmentOfDaphne >= investmentOfCleo)
    {
        investmentOfDaphne += 10;
        investmentOfCleo = investmentOfCleo*1.05;
        yeas += 1;
    }
    std::cout << "After " << yeas << "yeas, Cleo's investment exceed Daphne's. " << std::endl 
        << "At that time, Cleo's investment is : " << investmentOfCleo << ", Daphne's investment is: " << investmentOfDaphne << std::endl;
    return 0;
}

5、

#include <iostream>
#include <string>
#include <array>
 
int main()
{
    int salesOfMonths[12];
    std::array<std::string, 12> months = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
    int sumOfSales = 0;
    for(int i = 0; i < 12; i++)
    {
        std::cout << "pleas enter the valume of sales of " << months[i] << std::endl;
        std::cin >> salesOfMonths[i];
        sumOfSales += salesOfMonths[i];
    }

    std::cout << "the valume of sales of <<C++ For Fools>> this year is : " << sumOfSales << std::endl;
    return 0;
}

6、

#include <iostream>
#include <string>
#include <array>
 
int main()
{
    int salesOfMonths[3][12];
    std::array<std::string, 12> months = {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
    int sumOfSales[3] = {0, 0, 0};
    std::string years[3] = {"first year", "second year", "third year"};
    for(int j = 0; j < 3; j++)
    {
        for(int i = 0; i < 12; i++)
        {
            std::cout << "pleas enter the valume of sales of " << months[i] << " of "<< years[j] << std::endl;
            std::cin >> salesOfMonths[j][i];
            sumOfSales[j] += salesOfMonths[j][i];
        }
        std::cout << "the valume of sales of <<C++ For Fools>> of "<<  years[j] << " is : " << sumOfSales[j] << std::endl;
    }

    return 0;
}

7、

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

struct car{
    std::string producer;
    int madeYear;
};

int main()
{
    int countOfCar = 0;
    std::cout << "How many cars do you have ?" << std::endl;
    std::cin >> countOfCar;
    std::cin.get();   //非常关键的cin.get()，貌似每次使用getline之前都要有cin.get()
    if(countOfCar <= 0)
    {
        return -1;
    }

    struct car *pYourCars = new struct car[countOfCar];
    for(int i = 0; i < countOfCar; i++)
    {
        std::cout << "Car #" << (i+1) << ":" << std::endl;
        std::cout << "Please enter the make: ";
        getline(std::cin, pYourCars[i].producer);
        std::cout << "Please enter the year made: ";
        std::cin >> pYourCars[i].madeYear;
        std::cin.get();   //非常关键的cin.get()，貌似每次使用getline之前都要有cin.get()
    }

    std::cout << "Here is your collection: " << std::endl;
    for(int i = 0; i < countOfCar; i++)
    {
        std::cout << pYourCars[i].madeYear << " " << pYourCars[i].producer << std::endl;
    }

    delete [] pYourCars;
    return 0;
}

8、

#include <iostream>
#include <cstring>


int main()
{
    char word[100]={0};
    int countWords = 0;
    std::cout<< "Enter words (to stop, type the word done):" << std::endl;
    while(std::cin>>word)
    {
        if (strcmp(word,"done"))
        {
            countWords++;
        }
        else
        {
            break;
        }
    }
    std::cout << "Your entered a total of " << countWords << " words." << std::endl;
    return 0;
}

9、

#include <iostream>
#include <string>


int main()
{
    std::string word;
    int countWords = 0;
    std::string strEnd("done");
    std::cout<< "Enter words (to stop, type the word done):" << std::endl;
    while(std::cin>>word)
    {
        if (word == strEnd)
        {
            break;
        }
        countWords++;
    }
    std::cout << "Your entered a total of " << countWords << " words." << std::endl;
    return 0;
}

10、

#include <iostream>

int main()
{
    int rows = 0;
    std::cout<<"Enter number of rows: " << std::endl;
    std::cin >> rows;
    for(int i=1; i<=rows; i++)
    {
        for(int j=1; j<=rows-i;j++)
        {
            std::cout << ".";
        }
        for(int k=1; k<=i; k++)
        {
            std::cout << "*";
        }
        std::cout<<std::endl;
    }
    return 0;
}