main function
void
main()
Implementation
void main() {
print("Welcome to the rectangle calculator app.");
stdout.write("Please enter the tall of the rectangle: ");
String? rTall = stdin.readLineSync();
stdout.write("please enter the width of the rectangle: ");
String? rWidth = stdin.readLineSync();
double perimeter =
(double.parse(rTall ?? "0") + double.parse(rWidth ?? "0")) * 2;
print("The perimeter of the triangle is: $perimeter");
double area = double.parse(rTall ?? "0") * double.parse(rWidth ?? "0");
print("The area of the triangle is: $area");
print("Thank you for using the rectangle calculator app.");
print("Press any key to exit.");
stdin.readLineSync(); // Wait for user input before exiting
exit(2); // Exit the application
}