有理数就是可以表示为两个整数的比值的数字。一般情况下，我们用近似的小数表示。但有些时候，不允许出现误差，必须用两个整数来表示一个有理数。
这时，我们可以建立一个“有理数类”，下面的
class Rational {
private long ra;
private long rb;
private long gcd(long a, long b) {
if(b == 0) return a;
return gcd(b, a % b);
}
public Rational(long a, long b) {
ra = a;
rb = b;
long k = gcd(ra, rb);
if(k > 1) { //需要约分
ra /= k;
rb /= k;
}
}
// 加法
public Rational add(Rational x) {
return ________________________________________; //填空位置
}
// 乘法
public Rational mul(Rational x) {
return new Rational(ra*x.ra, rb*x.rb);
}
public String toString() {
if(rb == 1) return "" + ra;
return ra + "/" + rb;
}
}
使用该类的示例：
Rational a = new Rational(1,3);
Rational b = new Rational(1,6);
Rational c = a.add(b);
System.out.println(a + "+" + b + "=" + c);
class Rational {
private long ra;
private long rb;
private long gcd(long a, long b) {
if (b == 0)
return a;
return gcd(b, a % b);
}
public Rational(long a, long b) {
ra = a;
rb = b;
long k = gcd(ra, rb);
if (k > 1) { // 需要约分
ra /= k;
rb /= k;
}
}
// 加法
public Rational add(Rational x) {
return new Rational(ra * x.rb + x.ra * rb, rb * x.rb); // 填空位置
}
// 乘法
public Rational mul(Rational x) {
return new Rational(ra * x.ra, rb * x.rb);
}
public String toString() {
if (rb == 1)
return "" + ra;
return ra + "/" + rb;
}
}
public class Main {
public static vo
