#include <iostream>
#include <iomanip>
#include <string>
#include <cmath>
using namespace std;
int main()
{
double weight, sgrav, distance, speed, pweight, distanceplanet, travel;
char selection;
string planet;
cout << "Welcome to INTERPLANETARY TRAVEL PROGRAM!" << endl;
cout << "This program enables you to find out your travel time to the planet" << endl;
cout << "you want to travel to as well as your weight on that planet." << endl;
cout << "Please enjoy the program and find the perfect planet for you!" << endl;
cout << endl
<< endl
<< "INTERPLANETARY TRAVEL MENU" << endl
<< "--------------------------" << endl
<< "a) Mercury" << endl
<< "b) Venus" << endl
<< "c) Earth" << endl
<< "d) Mars" << endl
<< "e) Jupiter" << endl
<< "f) Saturn" << endl
<< "g) Uranus" << endl
<< "h) Neptune" << endl
<< "q) quit" << endl
<<endl
<< "Select a planet to travel to or q to quit the program: " << endl;
cin >> selection;
cout << "Please enter your weight (in lbs): " << endl;
cin >> weight;
cout << "Please enter the speed (in mile per hour) that you would like to travel at: " << endl
<< endl;
cin >> speed;
if (selection >= 'a' && selection <= 'h')
{
if (selection == 'a')
{
sgrav = 0.86;
pweight = (weight*sgrav);
planet = "Mercury";
distance = abs(36 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'b')
{
sgrav = 0.86;
pweight = (weight*sgrav);
planet = "Venus";
distance = abs(67 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'c')
{
sgrav = 1.00;
pweight = (weight*sgrav);
planet = "Earth";
distance = abs(93 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'd')
{
sgrav = 0.37;
pweight = (weight*sgrav);
planet = "Mars";
distance = abs(141 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'e')
{
sgrav = 2.64;
pweight = (weight*sgrav);
planet = "Jupiter";
distance = abs(483 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'f')
{
sgrav = 1.17;
pweight = (weight*sgrav);
planet = "Saturn";
distance = abs(886 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'g')
{
sgrav = 0.92;
pweight = (weight*sgrav);
planet = "Uranus";
distance = abs(1782 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
else if (selection == 'h')
{
sgrav = 1.44;
pweight = (weight*sgrav);
planet = "Neptune";
distance = abs(2793 - 93);
travel = (distance * speed);
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}
}
else if (selection == 'q')
{
cout << "You have chosen to quit the program. Thank you for using the program!" << endl;
}
else
{
cout << "You have entered an invalid selection." << endl;
}
//system("PAUSE");
return 0;
这么简单的程序非常漫长，我想知道是否有人会知道使用if-else语句输出信息的更有效方法，而不是复制粘贴到每种情况。另外，我在我声明我的双变量的行上得到了语法错误，并且它使用了半冒号，我不明白为什么。
答案 0 :(得分：0)
1）if (selection >= 'a' && selection <= 'h')用户可能会按下大写锁定，因此请考虑A~Z
2）（在我看来）退出应该是逻辑的开始。
3）您可以改用开关（选择）。 dafault：输入无效。再试一次。
4）将输出放在函数中并将变量传递给它，而不是再次写入相同的代码
void prn(float sgrav, int pweight, char arr[], float distance, float travel)
{
cout << "INTERPLANETARY TRAVEL: " << "Earth to " << planet << endl
<< "--------------------------------------------------" << endl
<< "Your weight on " << planet << ": " << setprecision(2) << pweight << " lbs" << endl
<< endl
<< "Your travel time to " << planet << ":" << endl
<< " In Hours: " << travel << " hours" << endl
<< " In Days : " << (travel / 24) << " days" << endl
<< " In years : " << (travel / 8760) << " years" << endl;
}