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  1. // Elaine Torrez                              Chapter 4 P. 125, #21
  2. /**************************************************************************
  3.  * GEOMETRY CALCULATOR
  4.  * ------------------------------------------------------------------------
  5.  * Displays a menu to calculate the area of a circle, rectangle, or triangle,
  6.  * or quit the program. Prompts for dimensions as needed, then shows the
  7.  * calculated area or an error message for invalid input.
  8.  * ------------------------------------------------------------------------
  9.  * INPUT
  10.  *   choice, radius, length, width, base, height
  11.  *
  12.  * OUTPUT
  13.  *   Area of the chosen shape, quit message, or error message
  14.  **************************************************************************/
  15.  
  16. #include <iostream>
  17. #include <iomanip>
  18. using namespace std;
  19.  
  20. int main()
  21. {
  22.     const double PI = 3.14159;  // Constant for circle area formula
  23.     int choice;                 // User's menu choice
  24.     double radius;              // Radius of circle
  25.     double length, width;       // Length and width of rectangle
  26.     double base, height;        // Base and height of triangle
  27.     double area;                // Calculated area
  28.  
  29.     // Display menu
  30.     cout << "Geometry Calculator\n"
  31.          << "1. Calculate the Area of a Circle\n"
  32.          << "2. Calculate the Area of a Rectangle\n"
  33.          << "3. Calculate the Area of a Triangle\n"
  34.          << "4. Quit\n\n"
  35.          << "Enter your choice (1-4): ";
  36.     cin >> choice;
  37.  
  38.     cout << fixed << setprecision(2);
  39.  
  40.     // Process menu choice
  41.     switch (choice)
  42.     {
  43.         case 1: // Circle
  44.             cout << "Enter the radius of the circle: ";
  45.             cin >> radius;
  46.             if (radius < 0)
  47.                 cout << "Error: Radius cannot be negative.\n";
  48.             else
  49.             {
  50.                 area = PI * radius * radius;
  51.                 cout << "The area of the circle is " << area << endl;
  52.             }
  53.             break;
  54.  
  55.         case 2: // Rectangle
  56.             cout << "Enter the length of the rectangle: ";
  57.             cin >> length;
  58.             cout << "Enter the width of the rectangle: ";
  59.             cin >> width;
  60.             if (length < 0 || width < 0)
  61.                 cout << "Error: Length and width cannot be negative.\n";
  62.             else
  63.             {
  64.                 area = length * width;
  65.                 cout << "The area of the rectangle is " << area << endl;
  66.             }
  67.             break;
  68.  
  69.         case 3: // Triangle
  70.             cout << "Enter the base of the triangle: ";
  71.             cin >> base;
  72.             cout << "Enter the height of the triangle: ";
  73.             cin >> height;
  74.             if (base < 0 || height < 0)
  75.                 cout << "Error: Base and height cannot be negative.\n";
  76.             else
  77.             {
  78.                 area = 0.5 * base * height;
  79.                 cout << "The area of the triangle is " << area << endl;
  80.             }
  81.             break;
  82.  
  83.         case 4: // Quit
  84.             cout << "Program ending.\n";
  85.             break;
  86.  
  87.         default:
  88.             cout << "Error: Please enter a number between 1 and 4.\n";
  89.     }
  90.  
  91.     return 0;
  92. }
  93.  
Success #stdin #stdout 0.01s 5268KB
comments (?)
stdin 
Standard input is empty
stdout 
Geometry Calculator
1. Calculate the Area of a Circle
2. Calculate the Area of a Rectangle
3. Calculate the Area of a Triangle
4. Quit

Enter your choice (1-4): Error: Please enter a number between 1 and 4.
https://ideone.com/poRJ7y
language:
C++ (gcc 8.3)
created:
3 days ago
visibility:
public

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