一些小程序的代码

自动生成随机数的代码：
import javax.swing.JOptionPane;

public class RandomInt {
   public static void main( String args[] )
   {
      int value;
      String output = "";

      for ( int i = 1; i <= 1000; i++ ) {
         value = 1 + (int) ( Math.random() * 1000 );
         output += value + "  ";
         
         if ( i % 5 == 0 )
            output += "\n";
      }

      JOptionPane.showMessageDialog( null, output,//通过窗口显示出来
         "20 Random Numbers from 1 to 1000",
         JOptionPane.INFORMATION_MESSAGE );

      System.exit( 0 );
   }
}

 二：关于参数类型的程序

// MethodOverload.java
// Using overloaded methods

public class MethodOverload {

    public static void main(String[] args) {
        System.out.println("The square of integer 7 is " + square(7));
        System.out.println("\nThe square of double 7.5 is " + square(7.5));
    }

    public static int square(int x) {
        return x * x;
    }

    public static double square(double y) {
        return y * y;
    }
}

可以看出参数的顺序和类型不一样出来的结果也是不一样的。