C++ Primer Plus 编程练习3.7

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//编程练习3.7
#include <iostream>
using namespace std;


int main1()
{
	
	const int Convert = 12;//1 feet=12 inches

	cout << "please input your height in inches: ________\b\b\b\b\b\b\b\b";

	int inches;
	cin >> inches;
	int height_feet = inches / Convert;
	int height_inches = inches % Convert;

	cout << " your height is: " << height_feet << " feet and " << height_inches << " inches. " << endl;

	return 0;
}


int main2()
{
	const double Feet2Inch = 12;
	const double Inch2Meter = 0.254;
	const double Kilo2Pound = 2.2;

	cout << " Please input your height in feet and inches! \n";
	cout << " The feet is: ";
	double height_feet = 0.0;
	cin >> height_feet;
	cout << " The inches is: ";
	double height_inch = 0.0; 
	cin >> height_inch;

	cout << " Your weight in pound is: ";
	double weight_pound = 0.0;
	cin >> weight_pound;

	double height_meter = (height_feet*Feet2Inch + height_inch)*Inch2Meter;
	double weight_kg = weight_pound / Kilo2Pound;

	double BMI = weight_kg / (height_meter*height_meter);
	cout << " Your BMI is: " << BMI << endl;

	return 0;
}


int main3()
{
	const int Convert = 60;

	cout << "Enter a latitude in degrees, minute and seconds:" << endl;
	cout << "First, enter the degrees: ";
	double degrees = 0;
	cin >> degrees;
	
	cout << "Next, enter the minucts of arc: ";
	double minutes = 0;
	cin >> minutes;
	cout << "Finally, enter the seconds of arc: ";
	double seconds = 0;
	cin >> seconds;

	cout << seconds / (Convert*Convert) << endl;
	double total = degrees+ seconds / (Convert*Convert) + minutes / Convert;

	cout << degrees << " degrees, " << minutes << " minutes, " << seconds << " seconds = " << total << " degrees." << endl;

	return 0;
}


int main4()
{

	const int D2H = 24;
	const int H2M = 60;
	const int M2S = 60;

	cout << "Enter the number of seconds: ";
	long long total_seconds = 0;
	cin >> total_seconds;

	int days = total_seconds / (D2H * H2M * M2S);
	int hours = ((total_seconds % (24 * 60 * 60)) / (60 * 60));
	int minutes = ((total_seconds % (60 * 60)) / 60);
	int seconds = (total_seconds % 60);

	cout << total_seconds << " seconds = " << days << " days, " << hours << " hours, " << minutes << " minutes, " << seconds << " seconds" << endl;

	return 0;
}


int main5()
{
	cout << "Enter the world's population :";
	long long world_population = 0;
	cin >> world_population;

	cout << "Enter the population of the US: ";
	long long US_population = 0;
	cin >> US_population;

	double rate = double(US_population) / (world_population);
	cout << "The population of the US is " << rate * 100 << "% of the world population." << endl;

	return 0;
}


int main6()
{
	//英里/加仑
	cout << "Enter the distance in mile: ";
	double miles;
	cin >> miles;
	cout << "Enter the  petrol: ";
	double gallon;
	cin >> gallon;
	cout << "Average fuel comsuption: " << miles / gallon << " mile/gallon" << endl;

	//欧洲风格
	cout << "Enter the distance in Km: ";
	double Km;
	cin >> Km;
	cout << "Enter the  petrol: ";
	double L;
	cin >> L;
	cout << "Average fuel comsuption: " << L/Km*100 << " L /100Km" << endl;

	return 0;
}

int main7()
{
	cout << "Enter the fuel comsuption in Europ standard: ";
	double E;
	cin >> E;

	double US = E / 12.41 * 19;
	cout << "The fuel comsuption in US standard is " << US << " mpg. " << endl;

	return 0;
}