[10주차 실습] 5월 4일 Problem Set

We want to construct the Calculator, Calc, Add, Sub, Mul, and Div classes in order for the attached main method to work properly.

• Calculator has one Calc field.

• The setCalculator method of Calculator takes one parameter and can receive Add, Sub, Mul, and Div objects as parameters. When each object is received, it can be set as the field.

• The run method of Calculator receives two integers through a scanner and performs calculations based on the object received by setCalculator.

• Calc is an abstract class that has two int operands as fields.

• The setValue method in Calc saves the two received values as operand values inside the object.

• The calculate method in Calc is declared as an abstract method for calculation.

• Add, Sub, Mul, and Div are classes that inherit from Calc.

 

package May04;

public abstract class Calc {
	protected int a, b;
	void setValue(int a, int b) {
		this.a = a;
		this.b = b;
	}
	
	abstract int calculate();

}


class Add extends Calc{
	@Override
	public int calculate(){
		int val=this.a+this.b;
		return val;
	}
}

class Sub extends Calc{
	@Override
	public int calculate(){
		int val=this.a-this.b;
		return val;
	}
	
}

class Mul extends Calc{
	@Override
	public int calculate(){
		int val=this.a*this.b;
		return val;
	}
}

class Div extends Calc{
	@Override
	public int calculate(){
		int val=this.a/this.b;
		return val;
	}
}

package May04;

import java.util.Scanner;

public class Calculator {
	Calc cal;
	Scanner scanner = new Scanner(System.in);
	
	void setCalculator(Calc cal) {
		this.cal = cal;
	}
	
	void run() {
		System.out.print("Write two integers >> ");
		int a = scanner.nextInt();
		int b = scanner.nextInt();
		cal.setValue(a, b);
		System.out.println(cal.calculate());
	}
}

package May04;

public class CalExample {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		Calculator calculator = new Calculator();
		calculator.setCalculator(new Add());
		calculator.run();
		calculator.setCalculator(new Div());
		calculator.run();
		calculator.setCalculator(new Sub());
		calculator.run();
		calculator.setCalculator(new Mul());
		calculator.run();
	}	

}

<실행결과>