Java理解类的封装（分数四则运算）

1.两个分数四则运算的结果仍然是分数。

uml图

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Rational

numerator:int denominator:int

setNumeratorAndDenominator(int,int):void add(Rational):Rational sub(Rational):Rational muti.... diu......

类设计完成后，进行编码

public class Rational {
    int numerator = 1; //分子
    int denominator = 1; //分母
    void setNumerator(int a){
        int c=f(Math.abs(a),denominator);
        numerator=a/c;
        denominator=denominator/c;
        if(numerator<0&&denominator<0){
            numerator=-numerator;
            denominator=-denominator;
        }
    }
    void setDenominator(int b){
        int c =f(numerator,Math.abs(b));
        numerator=numerator/c;