Statements in classes

[Raghuveer Mukkamalla]

hi,

i've the following class and would like explaination of why the expression
x = 24 gives a compilation error. i assume its because its outside a method, but am looking for detailed explaination.

public class Example281 {

int x = 12;
x = 24;

public static void go( int x) {
System.out.println(x);
}

public static void main (String[] args) {
Example281 ex281 = new Example281();
ex281.go(25);
System.out.println(ex281.x);
}
}

[Klaus Jesper]

Hm, why should anyone first declare an integer value and than change it without accessing a method or anything else? Makes no sense I guess? Please tell me what you want to achieve.

Klaus

[Paul Santa Maria]

Does this help?

public class Example281 {
 
  /* THIS FAILS (AT COMPILE TIME):
   * int x = 12;
   * x = 24;
   * public static void go( int x) {
   *   System.out.println(x);
   * }
   * COMPILE ERROR:
   * javac Example281.java =>
   *  Example281.java:4: <identifier> expected
   *    x = 24;
   *      ^
   *  Example281.java:4: cannot resolve symbol
   *  symbol  : class x
   *  location: class Example281
   *    x = 24;
   *    ^
   *  2 errors
   */
 
  /* THIS DOESN'T DIE ... BUT ONLY CHANGES THE *LOCAL* VARIABLE (NOT THE MEMBER VARIABLE) */
   *    int x = 12;
   *    public static void go( int x) {
   *      x = 24;     // "Actions" belong in "methods"
   *                  // This particular expression does *not* change "Exammple281.x", only the local "x"...
   *      System.out.println(x);
   */
 
  /* THIS WORKS: */
  static int x = 12;
  public static void go( int x) {
    x = 24;
    System.out.println(x);
  }
 
  /* AND THIS WORKS BETTER */
  public static void go2( int x) {
    Example281.x = x;
  }
 

  public static void main (String[] args) {
    Example281 ex281 = new Example281();
    System.out.println(ex281.x);
 
    ex281.go(25);
    System.out.println(ex281.x);
 
    ex281.go2(25);
    System.out.println(ex281.x);
  }
}