[code="java"]
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import com.shenchen.model.Item;
import com.shenchen.type.Types;
import com.shenchen.util.Calculator;
public class Main {
public static void main(String[] args) throws Exception, IOException {
InputStreamReader isr = new InputStreamReader(System.in);
BufferedReader br = new BufferedReader(isr);
Item item = new Item();
Double num1 = Double.parseDouble( br.readLine());
item.setNum1(num1);
System.out.println("请输入一个运算符号：");
String str = br.readLine();
switch (str) {
case "+":
item.setType(Types.JIA);
break;
case "-":
item.setType(Types.JIAN);
break;
case "*":
item.setType(Types.CHENG);
break;
case "/":
item.setType(Types.CHU);
break;
default:
System.out.println("符号错误！");
System.exit(0);
}
System.out.println("请输入一个数字：");
Double num2 = Double.parseDouble(br.readLine());
item.setNum2(num2);
new Calculator(item);
}
}
public class Item {
double num1;
double num2;
int type;
public void setNum1(double num1) {
this.num1 = num1;
}
public void setNum2(double num2) {
this.num2 = num2;
}
public void setType(int type) {
this.type = type;
}
public double getNum1() {
return num1;
}
public double getNum2() {
return num2;
}
public int getType() {
return type;
}
}
public class Types {
public final static int JIA = 1;
public final static int JIAN = 2;
public final static int CHENG =3;
public final static int CHU = 4;
}
import com.shenchen.model.Item;
import com.shenchen.type.Types;
public class Calculator {
double result;
public Calculator(Item item) {
double num1 = item.getNum1();
double num2 = item.getNum2();
switch (item.getType()) {
case Types.JIA:
result = num1+num2;
System.out.println(num1+"+"+num2+" = "+result);
break;
case Types.JIAN:
result = num1-num2;
System.out.println(num1+"-"+num2+" = "+result);
break;
case Types.CHENG:
result = num1*num2;
System.out.println(num1+"*"+num2+" = "+result);
break;
case Types.CHU:
result = num1/num2;
System.out.println(num1+"/"+num2+" = "+result);
break;
}
}
}
[/code]
将计算的抽一个接口出来ICalculator，具体计算实现该接口。如果要加功能，添加其它计算方法，添加实现类就好了，另外可以弄一个Factory负责创建这些Calculator。代码简单贴一下。
[code="java"]
public interface ICalculator {
public double calculate(double ...args);
}
[/code]
[code="java"]
//加法
public class PlusCalculator implements ICalculator {
@Override
public double calculate(double... args) {
double res = 0;
for(double arg:args)
res += arg;
return res;
}
}
[/code]
[code="java"]
//减法
public class MinusCalculator implements ICalculator {
@Override
public double calculate(double... args) {
if (args.length == 0)
return 0;
double res = args[0];
for (int i = 1; i < args.length; ++i) {
res -= args[i];
}
return res;
}
}
[/code]
[code="java"]
//平方
public class SquareCalculator implements ICalculator {
@Override
public double calculate(double... args) {
//只接受一个参数
if(args.length == 1)
return args[0]*args[0];
else
return 0;
}
}
[/code]
[code="java"]
//操作类型
public enum CalculatorType {
PlusCalculator,MinusCalculator,SquareCalculator;
}
[/code]
[code="java"]
//工厂
public class CalculatorFactory {
public static ICalculator getCalculator(CalculatorType type) {
ICalculator calculator = null;
switch (type) {
case MinusCalculator:
calculator = new MinusCalculator();
break;
case PlusCalculator:
calculator = new PlusCalculator();
break;
case SquareCalculator:
calculator = new SquareCalculator();
break;
default:
break;
}
return calculator;
}
}
[/code]
[code="java"]
//测试代码
public static void main(String[] args) {
double arg1 = 100;
double arg2 = 90;
double arg3 = 80;
ICalculator calculator = CalculatorFactory.getCalculator(CalculatorType.PlusCalculator);
System.out.println(calculator.calculate(arg1,arg2,arg3));
calculator = CalculatorFactory.getCalculator(CalculatorType.MinusCalculator);
System.out.println(calculator.calculate(arg1,arg2,arg3));
calculator = CalculatorFactory.getCalculator(CalculatorType.SquareCalculator);
System.out.println(calculator.calculate(arg1));
}
[/code]
这样写不好，应该用接口实现