所以我想这样做。我有一个运行开关的程序。从开关您可以选择1,2,3或4，每个选择都是一个形状。输入必要的条目以计算所述形状的面积。我完成了其中的所有4个。
现在，交换机的最后部分需要采取用户选择的内容并计算总面积。我无法弄清楚如何只在交换机的最后部分包含用户选择。
我的意思是，如果用户选择了圆形，而是三角形而不是矩形或正方形。如何让最终开关知道用户只选择了三角形和圆形而不是其他两个？
修改
好的，我现在改了。这是我更新的代码。目前正在遇到这个问题。它计算了一切，但我的if else声明。
EDIT2： 解决。
我遇到的问题（如果有人遇到过这个问题，我希望大多数人不会），我必须在每个案例中添加choices.push_back(2);，然后向量在if案例5中的if循环中正确调用它。
using namespace std;
double SLength, SWidth, SArea, RLength, RWidth, RArea, radius, CArea, base, height, TArea, total_area, labor, carpet, total, taxcost;
const double pi = 3.14;
const double cost = 2.45;
const double tax = .085;
vector<int> choices;
void AreaSquare() //creating an equation to be called to in my switch for fahrenheit conversion
{
SArea = pow(SLength,2.0);
}
void AreaRectangle() //creating an equation to be called to in my switch for fahrenheit conversion
{
RArea = (RWidth * RLength);
}
void AreaCircle() //creating an equation to be called to in my switch for fahrenheit conversion
{
CArea = pi * pow(radius,2.0);
}
void AreaTriangle() //creating an equation to be called to in my switch for fahrenheit conversion
{
TArea = 0.5 * base * height;
}
int main()
{
unsigned short choice;
do
{
cout << "Please choose from the following: " << "\n";
cout << "1: Square"<< "\n";
cout << "2: Rectangle"<< "\n";
cout << "3: Circle"<< "\n";
cout << "4: Triangle"<< "\n";
cout << "5: Total Area"<< "\n";
cout << "0: To Exit the Program"<< "\n";
cin >> choice;
system ("cls");
switch (choice)
{
case 1:
cout << "Please enter the Length: ";
cin >> SLength;
AreaSquare();
cout << "The area of the Square is " << SArea << "\n";
total_area += SArea;
system ("pause"); // pauses the program
system ("cls"); //clears the screen
break;
case 2:
cout << "Please enter the Length: ";
cin >> RLength;
cout << "Please enter the Width: ";
cin >> RWidth;
AreaRectangle();
cout << "The area of the Rectangle is " << RArea<< "\n";
total_area += RArea;
system ("pause"); // pauses the program
system ("cls"); //clears the screen
break;
case 3:
cout << "Please enter the Radius of the Circle: ";
cin >> radius;
AreaCircle();
cout << "The area of the Circle is: " << CArea<< "\n";
total_area += CArea;
system ("pause"); // pauses the program
system ("cls"); //clears the screen
break;
case 4:
cout << "Please enter the base of the Triangle: ";
cin >> base;
cout << "Please enter the height of the Triangle: ";
cin >> height;
AreaTriangle();
cout << "The area of the Triangle is " << TArea << "\n";
total_area += TArea;
system ("pause"); // pauses the program
system ("cls"); //clears the screen
break;
case 5:
for ( size_t i = 0; i < choices.size(); i++ )
{
if ( choices[i] == 1 )
{
cout << "Shape: Square" << "\n";
cout << "Length: " << SLength << "\n";
cout << "Area: " << SArea << "Square Feet" << "\n";
}
else if ( choices[i] == 2 )
{
cout << "Shape: Rectangle" << "\n";
cout << "Length: " << RLength << "\n";
cout << "Width: " << RWidth << "\n";
cout << "Area: " << RArea << "Square Feet"<< "\n";
}
else if ( choices[i] == 3 )
{
cout << "Shape: Circle" << "\n";
cout << "Radius: " << radius << "\n";
cout << "Area: " << CArea << "Square Feet" << "\n";
}
else if ( choices[i] == 4 )
{
cout << "Shape: Triangle" << "\n";
cout << "Base: " << base << "\n";
cout << "Height: " << height << "\n";
cout << "Area: " << TArea << "Square Feet" << "\n";
}
}
labor = (total_area / 50) * 35.72;
carpet = (total_area * 2.45);
taxcost = (labor + carpet) * tax;
total = (labor + carpet + taxcost) ;
cout << fixed << showpoint << setprecision(2);
cout << "Total area: $" << total_area << " Square Feet " << "\n";
cout << "Carpet Cost: $" << carpet << "\n";
cout << "Labor cost: $" << labor << "\n";
cout << "Tax: $" << taxcost << "\n";
cout << "Total Cost: $" << total << "\n";
case 0: //case in case user selects 0 the program will exit
cout << "Program is terminating..."<< endl;
system ("pause");
return 0;
break; //causes the prgram to execute the next statement outside the switch
default: //the third case incase the user enters an invalid option
cout << "That is not an option!" << endl;
cout << "Please try again." << endl;
cout << "\n" << endl;
cout << "\n" << endl;
cout << "\n" << endl;
system ("pause"); // pauses the program
system ("cls"); //clears the screen
break; //causes the program to execute the next statement outside the switch
}
} while (choice != 0);
}
答案 0 :(得分：0)
由于所有area *变量都是全局变量，因此默认情况下它们初始化为0。所以最简单的方法是添加所有区域*变量。
我可以告诉你正在学习编程，所以我只是说这个课程有很大的改进空间。
答案 1 :(得分：0)
您需要存储它们。你知道矢量吗？
std::vector<int> choices;
然后，在每个案例中：，执行此操作：
choices.push_back( n ); // where n = the input
仅在您需要确切知道所选内容和次数时才需要这样做。如果您只需要总面积，只需将总面积存储在具有适当范围的变量（如选项）中，并在每次迭代时附加每个形状的区域。
编辑：
好的，有几种方法可以做到这一点。使用您给定的代码库，我认为最简单的方法是在每种情况下将总面积存储在变量中，并将每个选项存储在一个向量中（参见上文）。在案例5：中，您需要循环遍历该向量并显示所有先前的选项，并在该循环之外打印总区域。
case 5:
for ( size_t i = 0; i < choices.size(); i++ ) {
if ( choices[i] == 0 ) {
// print out shape associated w/ zero
} else if ( choice[i] == 1 ) {
// print out shape associated w/ 1
}
//... etc.
}
std::cout << "Total area: " << total_area << std:::endl;
答案 2 :(得分：0)
你有很多问题。首先，你的程序的当前状态，即使没有你想要的额外位，已经破坏了缺少break语句和复制粘贴错误。我现在很累，很痛苦，所以也许我稍后会解释，但这是你程序的清理版本。总结是你不需要全局变量，如果你在交换机中的多个案例中重复某些事情，那么可能应该在交换机之外完成某些事情，具有有意义名称的枚举使得更容易分辨出你正在做什么而不是文字，for循环存在，所以你不必重复相同的代码六次，你只需要一个return语句，没有人真正使用do-while循环，如果你可以控制起始条件，你可以缓存区域结果一个额外的变量。
编辑：我没有意识到除了总面积之外你还想存储形状选择，所以我添加了一个std :: vector，它是一个动态数组，用于存储用户选择.I'故意遗漏存储宽度，高度，半径等，原因有两个：1）现在你已经看到我如何存储选择，你应该能够用你想要存储的任何东西复制那个逻辑，并且2）通过程序编程就像你在这里所做的那样，它的工作量超过它的价值。相反，在这一点上开始学习结构和类是更明智的。
#include <iostream>
#include <vector>
using namespace std;
const double pi = 3.14;
enum Option
{
Exit=0,
Square,
Rectangle,
Circle,
Triangle,
Totals,
Max
};
const char* const OptionNames[Max] =
{
"Exit",
"Square",
"Rectangle",
"Circle",
"Triangle",
"Total Area"
};
int main()
{
// Declare a container to store user selections in
vector<Option> selections;
// Declare a variable that stores the total area
double areaTotal = 0;
// Declare a variable to store the user's input and initialize it to something other than the exit condition
int userChoice = Totals;
// While the user hasn't opted to exit
while (Exit != userChoice)
{
// Prompt the user to select a shape
cout << "Please select a shape:\n";
// Iterate over all options, starting with square, and display their corresponding names
for (int i=Square; i<Max; ++i)
{
cout << i << ". " << OptionNames[i] << '\n';
}
// Show the Exit option last
cout << Exit << ". " << OptionNames[Exit] << '\n';
// Take the user's input
cin >> userChoice;
// If they entered a shape (not Exit or Total), save their selection
if (userChoice > Exit && userChoice < Totals)
selections.push_back(Option(userChoice)); // cast the int to an Option
// Evaluate the selection
switch (userChoice)
{
case Exit:
{
cout << "Program is terminating...\n";
break;
// Nothing else needs to be done here, as we are breaking out of the switch, and the while-loop's exit condition is now met
}
case Square:
{
cout << "Please enter the length of one side: ";
double length;
cin >> length;
double area = length * length;
cout << "The area of the Square is " << area << '\n';
areaTotal += area;
break;
}
case Rectangle:
{
cout << "Please enter the length: ";
double length;
cin >> length;
cout << "Please enter the width: ";
double width;
cin >> width;
double area = (length * width);
cout << "The area of the Rectangle is " << area << '\n';
areaTotal += area;
break;
}
case Circle:
{
cout << "Please enter the radius: ";
double radius;
cin >> radius;
double area = pi * pow(radius, 2.0);
cout << "The area of the Circle is: " << area << '\n';
areaTotal += area;
break;
}
case Triangle:
{
cout << "Please enter the base: ";
double base;
cin >> base;
cout << "Please enter the hight: ";
double height;
cin >> height;
double area = 0.5 * base * height;
cout << "The area of the triangle is " << area << '\n';
areaTotal += area;
break;
}
case Totals:
{
cout << "Your selections were:\n";
// Iterate over all selections except the last one, placing a comma and space after each one
int i;
for (i=0; i<selections.size()-1; ++i)
{
cout << OptionNames[selections[i]] << ", ";
}
// The last selection goes outside the for-loop, so we can put a newline after it instead of a comma
cout << OptionNames[selections[i]] << ".\n";
// Display the total area
cout << "The total area is: " << areaTotal << '\n';
break;
}
default:
{
cout << "That is not an option!\n";
cout << "Please try again.\n";
break;
}
}
}
system("pause");
return 0;
}