Question

我在第一个学期使用Java进行编程，我们刚开始进入OOP，我的代码遇到了一个小问题（毫不奇怪）。需要大师的帮助，你要弄清楚缺少什么，我知道我非常接近答案。基本上我给了分数类的分数驱动程序，我需要自己编写类。驾驶员的一切都必须保持原样。

这是驱动程序：

import java.util.Scanner;

public class FractionDemo
{

public static void main(String[] args)
{
Scanner stdIn = new Scanner(System.in);
Fraction c, d, x;       // Fraction objects

System.out.println("Enter numerator; then denominator.");
c = new Fraction(stdIn.nextInt(), stdIn.nextInt());
c.print();

System.out.println("Enter numerator; then denominator.");
d = new Fraction(stdIn.nextInt(), stdIn.nextInt());
d.print();

x = new Fraction();     // create a fraction for number 0


System.out.println("Sum:");
x.add(c).add(d);
x.print();

x.printAsDouble();

x = new Fraction(1, 1); // create a fraction for number 1

System.out.println("Product:");
x.multiply(c).multiply(d);
x.print();

x.printAsDouble();

System.out.println("Enter numerator; then denominator.");
x = new Fraction(stdIn.nextInt(), stdIn.nextInt());
x.printAsDouble();

}
} // end main

这是我的Fraction类。

public class Fraction
{
private int numerator;  // numerator of the fraction
private int denominator;   // denominator of the fraction

//**************************************************

public void Fraction()
{
numerator = 0;
denominator = 1;
}
// default constructor

public void Fraction(int n, int d)
{
numerator = n;
denominator = d;
}
//two parameter constructor

public void print()
{
System.out.println(numerator + "/" + denominator);
} //print fraction as n/d

public void printAsDouble()
{
System.out.printf("%f", numerator/denominator);
} //print fraction as double

public Fraction add(Fraction other)
{
//add
// calling object = calling obj + parameter
int n = this.numerator * other.denominator +
this.denominator * other.numerator;
int d = this.denominator * other.denominator;
this.numerator = n;
this.denominator = d;
return this;
}  
//multiply
public Fraction multiply(Fraction other)
{
int n = this.numerator * other.numerator;
int d = this.denominator * other.denominator;
this.numerator = n;
this.denominator = d;
return this;
}

} // end Fraction class

这是我收到的错误消息：

FractionDemo.java:19: error: constructor Fraction in class Fraction cannot be applied to given types;
    c = new Fraction(stdIn.nextInt(), stdIn.nextInt());
        ^
  required: no arguments
  found: int,int
  reason: actual and formal argument lists differ in length

FractionDemo.java:23: error: constructor Fraction in class Fraction cannot be applied to given types;
    d = new Fraction(stdIn.nextInt(), stdIn.nextInt());
        ^
  required: no arguments
  found: int,int
  reason: actual and formal argument lists differ in length
FractionDemo.java:35: error: constructor Fraction in class Fraction cannot be applied to given types;
    x = new Fraction(1, 1); // create a fraction for number 1
        ^
  required: no arguments
  found: int,int
  reason: actual and formal argument lists differ in length

FractionDemo.java:44: error: constructor Fraction in class Fraction cannot be applied to given types;
    x = new Fraction(stdIn.nextInt(), stdIn.nextInt());
        ^
  required: no arguments
  found: int,int
  reason: actual and formal argument lists differ in length
4 errors

Tool completed with exit code 1

Answer 1

你声明你的构造函数是这样的：

public void Fraction()
public void Fraction(int n, int d)

构造函数没有返回类型。声明他们：

public Fraction()
public Fraction(int n, int d)

分数驱动程序的分数类故障排除

1 个答案: