C++ Primer Plus(第6版）Chapter3编程题答案

    最近在学c++，并且坚持把每章节后面的编程练习题手敲了一遍，收获还蛮多的，想起来申请了优快云的博客一直都没写，有点尴尬（忘记在gitpages上的那个博客吧，N久没有写新东西了），趁着脑子里还残存着一些MarkDown，于是把代码贴上来吧！

---

第1题：

//  task1
#include <iostream>
using namespace std;

const int f_to_i = 12;## 标题 ##
int main(void)
{
    int n, feet, inches;
    cout << "Please input your height in the way of inchs: ___\b\b\b";      //使用退格键控制光标位置
    cin >> n;
    feet = n / f_to_i;
    inches = n % f_to_i;
    cout << "your height is " << feet << " feet and " << inches << " inches " << endl;
    cin.get();
    cin.get();
    return 0;
}

第2题：

//  task2
const int f_to_i = 12;
const double i_to_m = 0.0254;
const double p_to_k = (1 / 2.2);

int main(void)
{
    int feet, inches;
    cout << "Please input your feet: ";
    cin >> feet;
    cout << "and your inches: ";
    cin >> inches;
    double pounds;
    cout << "last is your pounds: ";
    cin >> pounds;
    int h1 = feet * f_to_i + inches;
    double h2 = h1 * i_to_m;
    double w = pounds * p_to_k;
    double bmi = w / (h2 * h2);
    cout << "your bmi is " << bmi << endl;
    cin.get();
    cin.get();
    return 0;
}

第3题：

// task3
const float d_to_m = 60.0;
const float m_to_s = 60.0;

int main()
{
    cout << "Enter a latitude in dgrees, minutes, and seconds:" << endl;
    cout << "First, enter the degrees: ";
    int d;
    cin >> d;
    cout << "Next, enter the minutes of arc: ";
    int m;
    cin >> m;
    cout << "Finally, enter the seconds of arc: ";
    int s;
    cin >> s;
    float degrees = float(d) + m / d_to_m + s / m_to_s / d_to_m;
    cout << d << " degrees, " << m << " minutes, " << s << " seconds = " << degrees << " degrees.";
    cin.get();
    cin.get();
    return 0;
}

第4题：

//  task4
const int dh = 24, hm = 60, ms = 60;

int main()
{
    cout << "Enter the number of seconds: ";
    long seconds;
    cin >> seconds;
    int d, h, m, s;
    s = seconds % ms;
    seconds = seconds / ms;
    m = seconds % hm;
    seconds = seconds / hm;
    h = seconds % dh;
    d = seconds / dh;
    cout << seconds << " seconds = " << d << " days, " << h << " hours, " << m << " minutes, " << s << " seconds. " << endl;
    cin.get();
    cin.get();
    return 0;
}

第5题：

// task 5
int main()
{
    long long all;
    cout << "Enter the world's population: ";
    cin >> all;
    long long usa;
    cout << "Enter the population of the US: ";
    cin >> usa;
    float percent = float(usa) / float(all) * 100;
    cout << "The population of the US is " << percent << "% of the world population.";
    cin.get();
    cin.get();
    return 0;
}

第6题：

// task6
int main()
{
    cout << "Enter the distance: ";
    float dis;
    cin >> dis;
    cout << "Enter the cost of oil: ";
    float oil;
    cin >> oil;
    cout << "Drive the 100 km will cost " << oil / dis * 100 << "L oil" << endl;
    cin.get();
    cin.get();
    return 0;
}

第7题：

// task7
int main()
{
    cout << "Enter the cost of oil Eupore: ";
    float eup;
    cin >> eup;
    cout << "Equarely, " << 62.14*3.875 / eup << "mpg." << endl;
    cin.get();
    cin.get();
    return 0;
}