Exercise : Syntax errors

• The following Java program has 9 errors. Can you find all of them?

  1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

  public class Parameters { public static void main() { double bubble = 867.5309; double x = 10.01; printer(double x, double y); printer(x); printer("barack", "obama"); System.out.println("z = " + z); } public static void printer(x, y double) { int z = 5; System.out.println("x = " + double x + " and y = " + y); System.out.println("The value from main is: " + bubble); } }

• Copy and paste the code into jGrasp and see if you can fix the errors.

Exercise - answer

1. line 5: cannot use variable y without declaring and initializing it
2. line 5: cannot declare the type of y in the method call
3. line 6: cannot call printer without the correct number of parameters (2, in this case)
4. line 7: cannot call printer by passing the correct type of parameters (double, in this case)
5. line 8: cannot refer to the variable z: it is in scope inside printer, not main
6. line 11: must provide a type for x
7. line 11: must provide a variable name for the second parameter
8. line 12: must refer to the parameters using the exact same spelling
9. line 13: cannot refer to variables in main that were not passed into printer as a parameter

Exercise - Corrected version

• Here is a corrected version of the program:

  public class Parameters {
      public static void main(String[] args) {
          double bubble = 867.5309;
          double x = 10.01;
          double y = 5.3;
          printer(double x, double y);
          printer(x, 0.0);
          printer("barack", "obama");
          int z = 5;
          System.out.println("z = " + z);
      }
  
      public static void printer(double x, double y) {
          System.out.println("x = " + x + " and y = " + y);
          System.out.println("The value from main is: " + bubble);
          int z = 5;
      }
  }