Discussion of Activity 1.1 - Executing some simple assignment statements

Sample solutions

1. You should get three compilation errors indicating that variables x, y and z "might not have been initialized" and therefore their values cannot be displayed by the System.out.println statements.

   This is an example of a situation where Java does not initialize variables to a default value. To correct these errors, you need to explicitly assign an initial value to each variable (as in the next task).

2. You should have added something like this

   x = 23;
   y = 333;
   z = 99;
   

   Note that it is important to use lower case names for x, y and z, as that is how they have been declared (since Java is case-sensitive).

   We could also have carried out declaration and initialization in one statement as follows:

   int x = 23;
   int y = 333;
   int z = 99;
   

   The output should be:

   After initialization:
   x contains 23
   y contains 333
   z contains 99
   

3. You should have added something like this

   x = x + 12;
   y = y - 100;
   z = x * y;
   System.out.println("After further calculations:");
   System.out.println("x contains " + x );
   System.out.println("y contains " + y );
   System.out.println("z contains " + z );
   

   The output should be:

   After initialization:
   x contains 23
   y contains 333
   z contains 99
   After further calculations:
   x contains 35
   y contains 233
   z contains 8155