Geometric Calculator

#include <iostream>

#include <cmath>

#include <iomanip>

using namespace std;

//declare constants.

const double PI = 3.14159;

int main()

{

int userChoice;

double circleRadius, areaCircle, rectangleLenght, width, rectangleArea, triangleBase, triangleHeight, triangleArea;

 // Display the menu and allow user to choose 1-4.

 cout << "\t\tGeometry Calculator"<<'\n';

 cout << "\t1. Calculate the Area of a Circle"<<'\n';

 cout << "\t2. Calculate the Area of a Rectangle"<<'\n';

 cout << "\t3. Calculate the Area of a Triangle"<<'\n';

 cout << "\t4. Quit\n\n";

 cout << "\tEnter your choice (1-4): ";

 cin >> userChoice;

 //format output precision.

 cout << fixed << showpoint << setprecision(2);

 // Validate menu userChoice.

 if (userChoice < 1 || userChoice > 4)

 {

 cout << endl;

 cout << "\t\t**Error!!!"<<'\n';

 cout<< "\tMenu option must be 1, 2, 3, or 4.\n\n";

 }

 // Respond to user's menu userChoice.

 switch (userChoice)

 {

 case 1: // Find area of a circle

 cout << endl;

 cout << "\t\tArea of a Circle\n\n";

 cout << "\t Please enter the radius of the circle: ";

 cin >> circleRadius;

 if (circleRadius < 0)

 {

 cout << '\n'<<endl;

 cout << "\t\t!!! Invalid Input Data"<<'\n'<<endl;

 cout<<"The radius of the circle must be a positive number and different from 0"<<'\n'<<endl;

 }

 else

 {

 areaCircle = PI * pow(circleRadius, 2.0);

 cout << "\tArea = " << areaCircle << endl;

 }

 break;

 case 2: // Find area of a rectangle

 //format output precision.

 cout << fixed << showpoint << setprecision(2);

 cout << endl;

 cout << "\t\tArea of a Rectangle\n\n";

 cout << "\tPlease enter the length of the rectangle: ";

 cin >> rectangleLenght;

 cout << "\tPlease enter the width of the rectangle: ";

 cin >> width;

 if (rectangleLenght <= 0 || width <= 0)

 {

 cout << '\n'<<endl;

 cout << "\t\t!!! Invalid Input Data"<<'\n'<<endl;

 cout<<"The Length and Width must be a positive number and different from 0"<<'\n'<<endl;

 }

 else

 {

 rectangleArea = rectangleLenght * width;

 cout << "\tArea = " << rectangleArea << " square units"<<endl;

 }

 break;

 case 3: // Find area of a triangle

 //format output precision.

 cout << fixed << showpoint << setprecision(2);

 cout << endl;

 cout << "\t\tArea of a Triangle\n\n";

 cout << "\tPlease enter the base of the triangle: ";

 cin >> triangleBase;

 cout << "\tPlease enter the height of the triangle: ";

 cin >> triangleHeight;

 if (triangleBase <= 0 || triangleHeight <= 0)

 {

 cout << '\n'<<endl;

 cout << "\t\t!!! Invalid Input Data"<<'\n'<<endl;

 cout<<"The Base and Height must be a positive number and different from 0"<<'\n'<<endl;

 }

 else

 {

 triangleArea = triangleBase * triangleHeight * 0.5;

 cout << "\tArea = " << triangleArea << endl;

 }

 break;

 case 4: // Quit the program

 cout << "\n\n\tThank you for using this software. ";

 cout<<endl;

 }

 system("pause");

 return 0;

 }