public class Rational{ private long numerator=0;//分子 private long denominator=1;//分母 public Rational() { super(); } public Rational(long numerator, long denominator) { // TODO Auto-generated constructor stub long gcd=gcd(numerator,denominator); this.numerator=((denominator>0)?1:-1)*numerator/gcd; this.denominator=Math.abs(denominator)/gcd; } //求两个数最大公约数以便约分 private static long gcd(long n, long d) { // TODO Auto-generated method stub long n1=Math.abs(n); long n2=Math.abs(d); int gcd=1; for(int k=1;k<=n1&&k<=n2;k++){ if(n1%k==0&&n2%k==0) gcd=k; } return gcd; } //获得有理数的分子或者分母 public long getNumerator(){ return numerator; } public long getDenominator(){ return denominator; } //有理数相加 public Rational add(Rational secondRational){ long n=numerator*secondRational.getDenominator()+ denominator*secondRational.getNumerator(); long d=denominator*secondRational.getDenominator(); return new Rational(n,d); } //有理数相减 public Rational subtract(Rational secondRational){ long n=numerator*secondRational.getDenominator()- denominator*secondRational.getNumerator(); long d=denominator*secondRational.getDenominator(); return new Rational(n,d); } //有理数相乘 public Rational multiply(Rational secondRational){ long n=numerator*secondRational.getNumerator(); long d=denominator*secondRational.getDenominator(); return new Rational(n,d); } //有理数相除 public Rational divide(Rational secondRational){ long n=numerator*secondRational.denominator; long d=denominator*secondRational.numerator; return new Rational(n,d); } public String toString(){ if(denominator==1) return numerator+""; if(numerator==0) return "0"; else return numerator+"/"+denominator; } public boolean equals(Object parm1){ if( this.denominator!=0 ) return true; else return false; } } public class Main { public static void main(String[] args) { Scanner sc=new Scanner(System.in); Rational R=new Rational(sc.nextInt(),sc.nextInt()); /* long numerator=sc.nextInt(); long denominator=sc.nextInt();*/ Rational secondRational=new Rational(sc.nextInt(),sc.nextInt()); /* System.out.println("分子："+R.getNumerator()); System.out.println("分母："+R.getDenominator()); System.out.println(R.toString()); */ if(R.equals(R)&secondRational.equals(secondRational)) { System.out.println("相加后："+R.add(secondRational).toString()); System.out.println("相减后："+R.subtract(secondRational).toString()); if(secondRational.getDenominator()==0||secondRational.getNumerator()==0) System.out.println("被除数不能为0"); else System.out.println("相除后："+R.divide(secondRational).toString()); System.out.println("相乘后："+R.multiply(secondRational).toString()); } else { System.out.println("分母不能为0"); } } } 来源：博客园
作者：不破爱花灬
链接：https://www.cnblogs.com/illusory---/p/11546544.html