Multi-state computer program, multi-state computer

Multi-state computer program, multi-state computer

1. Create a form

2. Create an Operator class with two operands and a method

Public abstract class Operator {public abstract int Calc (); // Number of computations public int NumLeft {get; set;} public int NumRight {get; set ;}}

3. Create an Add class

 public class Add:Operator    {        public override int Calc()        {            return this.NumLeft + this.NumRight;        }    }

4. Create a Sub class

 public    class Sub:Operator    {        public override int Calc()        {            return this.NumLeft - this.NumRight;        }    }

5. Create a Mul class

public    class Mul:Operator    {        public override int Calc()        {            return this.NumLeft * this.NumRight;        }    }

6. Create a div class

Public class Div: Operator {public override int Calc () {int result = 0; if (NumLeft = 0) {throw new Exception ("the divisor cannot be 0 ");} else {result = this. numLeft/this. numRight;} return result ;}}

7. Create a class similar to a factory

Public class Factory {// static return value Type parameter public static Operator cu (string Type) {Operator = null; switch (Type) {case "+ ": break = new Add (); break; case "-": break = new Sub (); break; case "*": break = new Mul (); break; case "/": condition = new Div (); break;} return condition ;}}

　　

8. Add

Private void btOk_Click (object sender, EventArgs e) {int num1 = Convert. toInt32 (txtLfet. text); string Signature = cb. text; int num2 = Convert. toInt32 (txtRight. text); // 04. call the static method of the Factory, input the type, and obtain the return value Operator part = Factory. cu (partial); part. numLeft = num1; part. numRight = num2; int result = 0; // 05. call the Calc () corresponding to the parent variable to complete the calculation and receive the return value try {result = part. calc ();} catch (Exception ex) {MessageBox. show (ex. message);} // 06. label1.Text = result is displayed in the Label. toString ();}