可變 字符 字符串表 bsp stat oid hat return div

1.2.16有理數。為有理數實現一個可變數據類型Rational,支持加減乘除操作。無需測試溢出(請見練習1.2.17),只需使用兩個long型實例變量表示分子和分母來控制溢出的可能性。使用歐幾裏得算法來保證分子和分母沒有公因子。編寫一個測試用例檢測你實現的所有方法。
public class Rational
Rational(int numerator. int denominator)
Rational plus(Rational b) 該數與b之和
Rational minus(Rational b) 該數與b之差
Rational times(Rational b) 該數與b之積
Rational divides(Rational b) 該數與b之商
boolean equals(Rational that) 該數與that相等嗎
String toString() 對象的字符串表示
答：

public class Rational
{
private final long myNumerator;
private final long myDenominator;

private long gcd(long p,long q)
{
if (q==0) return p;
return gcd(q,p%q);
}

public Rational(long numerator, long denominator)
{
long gcdValue=gcd(numerator,denominator);
myNumerator=numerator/gcdValue;
myDenominator=denominator/gcdValue;
}

public long Numberator()
{
return myNumerator;
}

public long Denominator()
{
return myDenominator;
}

public Rational plus(Rational b)
{
long gcdValue=gcd(this.Denominator(),b.Denominator());
long n=this.Numberator()*b.Denominator()/gcdValue+b.Numberator()*this.Denominator()/gcdValue;
long d=this.Denominator()*b.Denominator()/gcdValue;
//
gcdValue=gcd(d,n);
n=n/gcdValue;
d=d/gcdValue;
return new Rational(n,d);
}

public Rational minus(Rational b)
{
long gcdValue=gcd(this.Denominator(),b.Denominator());
long n=this.Numberator()*b.Denominator()/gcdValue-b.Numberator()*this.Denominator()/gcdValue;
long d=this.Denominator()*b.Denominator()/gcdValue;
//
gcdValue=gcd(d,n);
n=n/gcdValue;
d=d/gcdValue;
return new Rational(n,d);
}

public Rational times(Rational b)
{
long gcdValue1=gcd(this.Numberator(),b.Denominator());
long gcdValue2=gcd(this.Denominator(),b.Numberator());
//
long n=this.Numberator()/gcdValue1*b.Numberator()/gcdValue2;
long d=this.Denominator()/gcdValue2*b.Denominator()/gcdValue1;
return new Rational(n,d);
}

public Rational divides(Rational b)
{
long gcdValue1=gcd(this.Numberator(),b.Numberator());
long gcdValue2=gcd(this.Denominator(),b.Denominator());
//
long n=this.Numberator()/gcdValue1*b.Denominator()/gcdValue2;
long d=this.Denominator()/gcdValue2*b.Numberator()/gcdValue1;
return new Rational(n,d);
}

public boolean equals(Rational that)
{
if(this==that) return true;
if(that==null) return false;
if(this.Numberator()!=that.Numberator()) return false;
if(this.Denominator()!=that.Denominator()) return false;
return true;
}

public String toString()
{
return this.Numberator()+"/"+this.Denominator();
}

public static void main(String[] args)
{
long Numberator=Long.parseLong(args[0]);
long Denominator=Long.parseLong(args[1]);

Rational r1=new Rational(Numberator,Denominator);
Rational r2=new Rational(Numberator,Denominator);
//=
StdOut.printf("r1=%-7s r2=%-7s r1=rs2 is:%s\n",r1.toString(),r2.toString(),r1.equals(r2));
//+
StdOut.printf("r1=%-7s r2=%-7s r1+rs2=%-7s\n",r1.toString(),r2.toString(),r1.plus(r2));
//-
StdOut.printf("r1=%-7s r2=%-7s r1-rs2=%-7s\n",r1.toString(),r2.toString(),r1.minus(r2));
//*
StdOut.printf("r1=%-7s r2=%-7s r1*rs2=%-7s\n",r1.toString(),r2.toString(),r1.times(r2));
// /
StdOut.printf("r1=%-7s r2=%-7s r1/rs2=%-7s\n",r1.toString(),r2.toString(),r1.divides(r2));

}
}

Algs4-1.2.16有理數