5.2 测试与封装

//源代码

package avshabi;
import java.util.StringTokenizer;
public class Calculator {
int numerator; // 分子
int denominator; // 分母

Calculator(){
}

Calculator(int a,int b){
if(a == 0){
numerator = 0;
denominator = 1;
}
else{
setNumeratorAndDenominator(a,b);
}
}

void setNumeratorAndDenominator(int a, int b){ // 设置分子和分母
int c = f(Math.abs(a),Math.abs(b)); // 计算最大公约数
numerator = a / c;
denominator = b / c;
if(numerator<0 && denominator<0){
numerator = - numerator;
denominator = - denominator;
}
}

int getNumerator(){
return numerator;
}

int getDenominator(){
return denominator;
}

int f(int a,int b){ // 求a和b的最大公约数
if(a < b){
int c = a;
a = b;
b = c;
}
int r = a % b;
while(r != 0){
a = b;
b = r;;
r = a % b;
}
return b;
}

Calculator add(Calculator r){ // 加法运算
int a = r.getNumerator();
int b = r.getDenominator();
int newNumerator = numerator * b + denominator * a;
int newDenominator = denominator * b;
Calculator result = new Calculator(newNumerator,newDenominator);
return result;
}

Calculator sub(Calculator r){ // 减法运算
int a = r.getNumerator();
int b = r.getDenominator();
int newNumerator = numerator * b - denominator * a;
int newDenominator = denominator * b;
Calculator result = new Calculator(newNumerator,newDenominator);
return result;
} 

Calculator muti(Calculator r){ // 乘法运算
int a = r.getNumerator();
int b = r.getDenominator();
int newNumerator = numerator * a;
int newDenominator = denominator * b;
Calculator result = new Calculator(newNumerator,newDenominator);
return result;
}

Calculator div(Calculator r){ // 除法运算
int a = r.getNumerator();
int b = r.getDenominator();
int newNumerator = numerator * b;
int newDenominator = denominator * a;
Calculator result = new Calculator(newNumerator,newDenominator);
return result;
}

// 封装了具体运算，主要为对输入进行转换，对输出封装
public static void compute(String data1,String operation,String data2){
StringTokenizer fenxi = new StringTokenizer(data1,"/");
int data1_1 = Integer.parseInt(fenxi.nextToken());
int data1_2 = Integer.parseInt(fenxi.nextToken());
fenxi = new StringTokenizer(data2,"/");
int data2_1 = Integer.parseInt(fenxi.nextToken());
int data2_2 = Integer.parseInt(fenxi.nextToken());

Calculator r1 = new Calculator(data1_1,data1_2);
Calculator r2 = new Calculator(data2_1,data2_2);

Calculator result;
int a,b;
if(operation.equals("+")){
result = r1.add(r2);
a = result.getNumerator();
b = result.getDenominator();
System.out.println(data1+" "+operation+" " +data2+" = " + a + "/" + b);
}

if(operation.equals("-")){
result = r1.sub(r2);
a = result.getNumerator();
b = result.getDenominator();
System.out.println(data1+" "+operation+" " +data2+" = " + a + "/" + b);
}

if(operation.equals("*")){
result = r1.muti(r2);
a = result.getNumerator();
b = result.getDenominator();
System.out.println(data1+" "+operation+" " +data2+" = " + a + "/" + b);
}

if(operation.equals("/")){
result = r1.div(r2);
a = result.getNumerator();
b = result.getDenominator();
System.out.println(data1+" "+operation+" " +data2+" = " + a + "/" + b);
}
}
}

// 测试类

package avshabi;

import java.util.Scanner;
public class TestCal {
public static void main(String[] args) {
// TODO Auto-generated method stub

// 用户输入两分数和运算符
Scanner input = new Scanner(System.in);
System.out.println("请用户输入第一个分数(格式a/b)");
String data1 = input.next();
System.out.println("请用户输入要进行运算的运算符(+-*/)");
String operation = input.next();
System.out.println("请用户输入第二个分数(格式c/d)");
String data2 = input.next();

// 根据用户输入进行具体运算
Calculator cal = new Calculator();
System.out.println("运算结果为:");
cal.compute(data1, operation, data2);
//    }
}
}

//JUINT测试应用举例
package avshabi;

import static org.junit.Assert.*;

import org.junit.Test;

public class CalculatorTest {
Calculator cal = new Calculator();
    @Test
    public void testSetNumeratorAndDenominator() {
        cal.setNumeratorAndDenominator(2, 3);
    }

    @Test
    public void testF() {
        cal.f(1, 2);
    }

    @Test
    public void testSub() {
        cal.sub(cal);
    }

    @Test
    public void testCompute() {

        cal.compute("1/2", "+", "1/3");
    }

}