exercise6_9.java

Introduction to java programming 一书中所有编程练习部分的源码

public class Exercise6_9 {
  public static void main(String[] args) {
    Int n1 = new Int(5);
    System.out.println("n1 is even? " + n1.isEven());
    System.out.println("n1 is prime? " + n1.isPrime());
    System.out.println("5 is prime? " + Int.isPrime(15));
  }
}

class Int {
  private int value;
  
  public int getValue() {
      return value;
  }
  
  public Int(int value) {
    this.value = value;
  }
  
  public boolean isPrime() {
    return isPrime(value);
  }
  
  public static boolean isPrime(int num) {
    if ((num ==1) || (num ==2)) {
      return true;
    }

    for (int i=2; i<=num/2; i++) {
      if (num%i == 0)
        return false;
    }

    return true;
  }
  
  public static boolean isPrime(Int o) {
    return isPrime(o.getValue());
  }

  public boolean isEven() {
    return isEven(value);
  }
  
  public static boolean isEven(int n) {
    return n % 2 == 0;
  }
  
  public static boolean isEven(Int n) {
    return isEven(n.getValue());
  }
  
  public boolean equals(int anotherNum) {
    return value == anotherNum;
  }
  
  public boolean equals(Int o) {
    return value == o.getValue();
  }
}