用java具体代码实现分数(即有理数)四则运算

1，背景

Java老师布置了一个关于有理数运算的题目，因为参考书上有基本代码，所以自己主要是对书上代码做了一点优化，使其用户交互性更加友好以及代码封装性更强

2，说明:

分数也称作有理数，是我们很熟悉的一种数。有时希望程序能对分数进行四则运算，而且两个分数四则运算的结果仍然是分数。下面是具体实现

3，java代码具体实现

3.1 运算类封装

package Rational;

import java.util.StringTokenizer;
/**
 * @author sunkun
 * 分数四则运算
 */
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);
		}
	}
}

3.2 测试类

package Rational;

import java.util.Scanner;
/**
 * @author sunkun
 * 为了测试分数四则运算
 * */
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);
//	  }		
	}
}