[数据结构与算法]C++Primer Plus 第六版课后题编程练习记录（一）

最近开始学习C++，用C++primer plus 这本书，里面每个章节有复习题和编程练习题，这里只记录一下书中的编程练习题。（复习题都有参考答案，网上很容易就能找到，有需要的我发你）。
第二章的练习题与比第三章的简单，所以直接从第三章开始记录，第三章的搞懂做第二章的习题没有任何问题。
第三章 处理数据
3.7 编程练习
3.1

//习题3.1 
#include<iostream>
int main()
{
	using namespace std;
	const int conversion_factor = 12;
	int body_height_inchs;
	int body_height_foots;
	int inch1;
	cout << "Enter your height is " << "__\b\b" << " inchs "; //\b表示退格符
	cin >> body_height_inchs;
	cout << "your height is " << body_height_inchs << " inchs "<<endl;
	body_height_foots = body_height_inchs / conversion_factor;
	inch1 = body_height_inchs % conversion_factor;
	//use foots and inchs
	cout << body_height_inchs << " inchs are " << body_height_foots << " foots " << "and " << inch1 << " inchs\n";

	return 0;

}

3.2

//习题3.2
#include<iostream>
int main()
{
	using namespace std;
	const int in_t_fo_conversion_factor = 12;//英寸英尺转换因子，1英尺=12英寸
	const double m_to_in_conversion_factor = 0.0254;//英寸和米转换因子，1英寸=0.0254米
	const double k_to_p_conversion_factor = 2.2;//千克与磅转换因子，1千克=2.2磅

	cout.setf(ios_base::fixed, ios_base::floatfield);//fixed-point,将小数点后数字都显示出来

	int body_height_inchs;//英寸
	int body_height_foots;//英尺
	int body_weights_p;//磅

	double body_height_m;
	double body_weights_k;
	double BMI;

	cout << "Enter your height is (units foots)";
	cin >> body_height_foots;
	cout << "Enter your height is (units inch)";
	cin >> body_height_inchs;
	cout << "Enter your weight is (units pounds)";
	cin >> body_weights_p;

	cout << "your height is " << body_height_foots << " foot "<<"and "<< body_height_inchs<<" inchs.\n";
	cout << "your weight is " << body_weights_p << " pounds. " << endl;
	cout << "start convert !!" << endl;
	
	body_height_m = (body_height_foots * in_t_fo_conversion_factor + body_height_inchs) * m_to_in_conversion_factor;
	cout << "your heignt is " << body_height_m << " m " << endl;
	body_weights_k = body_weights_p /k_to_p_conversion_factor;
	cout << "your weight is " << body_weights_k << " kg " << endl;
	BMI = body_weights_k / body_height_m / body_height_m;
	cout << "your BMI is " << BMI << endl;

	return 0;

}

3.3

//习题3.3
#include<iostream>
int main()
{
	using namespace std;
	const int degrees_to_minutes_conversion_factor = 60;//转换因子
	const int minutes_to_seconds_conversion_factor = 60;
	int degrees;
	int minutes;
	int seconds;

	double act_latitude;
	//cout.setf(ios_base::fixed, ios_base::floatfield);//fixed-point,将小数点后数字都显示出来,将这句注释结果就和书中结果一样
	//cout 默认只显示6位有效数字
	cout << "Enter a latitude in degrees, minutes, and seconds:\n";
	cout << "First, enter the degrees: ";
	cin >> degrees;
	cout << "Next, enter the minutes of arc: ";
	cin >> minutes;
	cout << "Finally, enter the seconds of arc: ";
	cin >> seconds;

	act_latitude = double(degrees) + (double(minutes) / degrees_to_minutes_conversion_factor) + (double(seconds) / minutes_to_seconds_conversion_factor / degrees_to_minutes_conversion_factor);//做强制类型转换，先将int型转换为double型再去计算
	cout << degrees << " degrees, " << minutes << " minutes, " << seconds << " seconds = " << act_latitude << " degrees\n";

	return 0;

}

3.4

习题3.4
#include<iostream>
int main()
{
	using namespace std;
	const int perday_to_perhour = 24;

	const int perhour_to_perminute = 60;//转换因子
	const int perminute_to_second = 60;
	int days;
	int minutes;
	int hours;
	int seconds;
	long long total_seconds;//数据过大采用long或long long型
	
	//cout.setf(ios_base::fixed, ios_base::floatfield);//fixed-point,将小数点后数字都显示出来,将这句注释结果就和书中结果一样
	//cout 默认只显示6位有效数字
	cout << "Enter the number of seconds: ";
	cin >> total_seconds;
	
	days = total_seconds /(perday_to_perhour * perhour_to_perminute * perminute_to_second);
	hours = total_seconds / perminute_to_second / perhour_to_perminute % perday_to_perhour;
	minutes = total_seconds / perminute_to_second % perhour_to_perminute;
	seconds = total_seconds % perminute_to_second;

	cout << total_seconds << " seconds = " << days << " days, " << hours << " hours, " << minutes << " minutes, "<< seconds<<" seconds \n";

	return 0;

}

3.5

习题3.5
#include<iostream>
int main()
{
	using namespace std;
	long long world_population;
	long long native_population;
	double percengtage;
	//cout.setf(ios_base::fixed, ios_base::floatfield);//fixed-point,将小数点后数字都显示出来,将这句注释结果就和书中结果一样
	
	cout << "Enter the world population: ";
	cin >> world_population;
	cout << "Enter the population of the US: ";
	cin >> native_population;
	//percengtage = double(native_population) / double(world_population) * 100;
	percengtage = double(native_population) / (world_population) * 100;
	//上述两种语句的计算结果是一致的，因为当有一个操作数类型是double，则将另一个操作数转换为double。这是C++的自动类型转换
	//在不同类型的算数运算中，会有一些转换，其中浮点型优先级最高，依次是long double,double,float，然后是整型，整型级别依次是long long,long,int,short和sighed char,有符号和无符号整型排列顺序相同
	//类型char,signed char 和unsigned char 级别相同，bool的级别最低。wchar_t、char16_t和char32_t级别与其底层类型相同
	cout << " The population of the US is " << percengtage << "% of the world population.\n";
	return 0;

}

3.6

习题3.6
#include<iostream>
int main()
{
    using namespace std;
    char SIGH;
    cout << "Choice your input 'm'indicates that the units entered are miles and gallons. OR input 'k' indicates the units entered are kilometers and liters " << endl;
    cout << "input is _\b";
    cin >> SIGH;
 
    if (SIGH == 'm')//按照英里和加仑为单位来输入距离和汽油量
    {
        double m_distance;
        double m_gasoline;
        cout << "Enter the miles of distance you have driven:";
        cin >> m_distance;
        cout << "Enter the gallons of gasoline you have used:";
        cin >> m_gasoline;
        cout << "Your car can run " << m_distance / m_gasoline << " miles per gallon\n";
        
    }
    if (SIGH == 'k')//以公里和升为单位输入距离和汽油量
    {
        double k_distance;
        double k_gasoline;
        cout << "Enter the distance in kilometers:";
        cin >> k_distance;
        cout << "Enter the petrol in liters:";
        cin >> k_gasoline;
        cout << "In European style: " << "your can used " << 100 * k_gasoline / k_distance << " liters of petrol per 100 kilometers\n";
    }
   
    return 0;

}

3.7

//习题3.7
#include<iostream>
int main()
{
    using namespace std;
    cout << "Enter the automobile gasoline consumption figure in\n";
    cout << "Europeanstyle(liters per 100 kilometers):";
    double European_style;
    cin >> European_style;
    cout << "Converts to U.S. style(miles per gallon):" << endl;
    cout << European_style << "L/100Km=" << 62.14 * 3.875 / European_style << "mpg\n";//100公里=62.14英里，1加仑=3.785升，当耗油量为12.4L/100km时，其美式耗油量=62.14/(12.4/3.785)=62.14*3.785/12.4约等于19mpg.
    return 0;
}