C++ Primer Plus-3.7编程练习-第2题和第5题

感觉第三章代码都差不多，就写两个吧。
第二题答案：

#include <iostream>
using namespace std;
const double trans=12;
const double shenggao=0.0254;
const double tizhong=2.2;

int main() {

    double h, m, w, hm;
    cout << "请输入你的身高:";
    cin >> h >> m;
    cout << "请输入你的体重:";
    cin >> w;
    hm = h * trans + m;
    cout << "统一身高后：" << hm << endl;
    cout << "转换为米后：" << hm*shenggao << endl;
    cout << "体重转换单位后：" << w*tizhong << endl;
    cout << "BMI:" << (w*tizhong / hm*shenggao) * (w*tizhong / hm*shenggao) << endl;

    return 0;
}

运行结果：

请输入你的身高:1 12
请输入你的体重:5
统一身高后：24
转换为米后：0.6096
体重转换单位后：11
BMI:0.000135528

第五题答案：

#include <iostream>
using namespace std;

int main() {

    long long h, m;
    cout << "Enter the world's population:";
    cin >> h;
    cout << "Enter the population of the US:";
    cin >> m;
    cout << "The population of the US is " << (double(m) / double(h))*100 << "% of the world population.";

    return 0;
}

运行结果：

Enter the world's population:6898758899
Enter the population of the US:310783781
The population of the US is 4.50492% of the world population.