我的主要功能的第5行出现错误...该行显示：
System.out.println( "The fractional number is " + myRational.Rational(s) );
发生的错误告诉我
The method Rational(String) is undefined for the type Assignment13.Rational.
任何帮助或建议，将不胜感激。
import java.math.BigInteger;
import java.util.Scanner;
public class Assignment13 {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.println("Enter a decimal number: ");
String s = input.next();
Rational myRational = new Rational();
System.out.println( "The fractional number is " + myRational.Rational(s) );
}
public class Rational extends Number implements Comparable<Rational> {
// Data fields for numerator and denominator
private BigInteger numerator = BigInteger.ZERO;
private BigInteger denominator = BigInteger.ONE;
/** Construct a rational with default properties */
public Rational() {
this(BigInteger.ZERO,BigInteger.ONE);
}
/** Construct a rational with specified numerator and denominator */
public Rational(BigInteger numerator, BigInteger denominator) {
BigInteger gcd = gcd(numerator, denominator);
this.numerator= (denominator.compareTo(BigInteger.ZERO) > 0 ? BigInteger.ONE :
new BigInteger("-1")).multiply(numerator.divide(gcd));
this.denominator = denominator.divide(gcd);
}
public Rational(String decimal) {
int index = (decimal.contains(".")) ? decimal.indexOf('.') : decimal.indexOf('/');
BigInteger d;
BigInteger n;
// if string is in decimal form
if (decimal.contains(".")) {
int power = decimal.substring(index + 1, decimal.length()).length();
d = new BigInteger ("Math.pow(10,power)");
n = new BigInteger(new StringBuilder(decimal).deleteCharAt(index).toString());
} else {
// if string contains '/'
n = new BigInteger(decimal.substring(0, index));
d = new BigInteger(decimal.substring (index + 1, decimal.length()));
}
BigInteger gcd = gcd(n, d);
this.numerator = ((d.compareTo(BigInteger.ZERO) > 0) ? BigInteger.ONE : new BigInteger("-1")).multiply(n).divide(gcd);
this.denominator = d.abs().divide(gcd);
}
/** Find GCD of two numbers */
private BigInteger gcd(BigInteger n, BigInteger d) {
BigInteger n1 = n.abs();
BigInteger n2 = d.abs();
BigInteger gcd = BigInteger.valueOf(1);
for (BigInteger k = BigInteger.valueOf(1); k.compareTo(n1) <= 0 && k.compareTo(n2) <= 0; k.add(BigInteger.ONE)) {
if (n1.mod(k) == BigInteger.ZERO && n2.mod(k) == BigInteger.ZERO)
gcd = k;
}
return gcd;
}
/** Return numerator */
public BigInteger getNumerator() {
return numerator;
}
/** Return denominator */
public BigInteger getDenominator() {
return denominator;
}
/** Add a rational number to this rational */
public Rational add(Rational secondRational) {
BigInteger n = numerator.multiply(secondRational.getDenominator()).add(denominator.multiply(secondRational.getNumerator()));
BigInteger d = denominator.multiply(secondRational.getDenominator());
return new Rational(n, d);
}
/** Subtract a rational number from this rational */
public Rational subtract(Rational secondRational) {
BigInteger n = numerator.multiply(secondRational.getDenominator()).subtract(denominator.multiply(secondRational.getNumerator()));
BigInteger d = denominator.multiply(secondRational.getDenominator());
return new Rational(n, d);
}
/** Multiply a rational number by this rational */
public Rational multiply(Rational secondRational) {
BigInteger n = numerator.multiply(secondRational.getNumerator());
BigInteger d = denominator.multiply(secondRational.getDenominator());
return new Rational(n, d);
}
/** Divide a rational number by this rational */
public Rational divide(Rational secondRational) {
BigInteger n = numerator.multiply(secondRational.getDenominator());
BigInteger d = denominator.multiply(secondRational.numerator);
return new Rational(n, d);
}
@Override
public String toString() {
if (denominator.compareTo(BigInteger.ONE) == 0)
return numerator + "";
else
return numerator + "/" + denominator;
}
@Override // Override the equals method in the Object class
public boolean equals(Object other) {
if (((this.subtract((Rational)(other))).getNumerator()).compareTo(BigInteger.ZERO) == 0)
return true;
else
return false;
}
@Override // Implement the abstract intValue method in Number
public int intValue() {
return (int)doubleValue();
}
@Override // Implement the abstract floatValue method in Number
public float floatValue() {
return (float)doubleValue();
}
public BigInteger bigIntegerValue() {
return numerator.multiply(new BigInteger("1").divide(denominator));
}
@Override // Implement the doubleValue method in Number
public double doubleValue() {
return numerator.divide(denominator).doubleValue();
}
@Override // Implement the abstract longValue method in Number
public long longValue() {
return (long)doubleValue();
}
@Override // Implement the compareTo method in Comparable
public int compareTo(Rational o) {
if (this.subtract(o).getNumerator().compareTo(BigInteger.ZERO) > 0)
return 1;
else if (this.subtract(o).getNumerator().compareTo(BigInteger.ZERO) < 0)
return -1;
else
return 0;
}
}
}
答案 0 :(得分：0)
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传递给类String s的构造函数，并从有效的实例Assignment13.Rational中调用它。没有理由创建一个新对象，也没有理由再使用另一个对象。
myRational已经是myRational。如果要从Rational打印新创建的对象，请执行以下操作：
String s或者最好将类设为System.out.println("The fractional number is " + new Assignment13().new Rational(s));
，然后可以通过以下方式进行访问：
static在同一班上new Rational(s))，因为它们是new Assignment13.Rational(s)。在两种情况下，您都可以省略以下行：
public我建议您覆盖方法Object::toString，该方法默认情况下在打印到控制台时。