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Thread: use of System.out.println(""); error....

  1. #1
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    Default use of System.out.println(""); error....

    Hi all,
    Cant we use System.out.println within class scope ? Like the one shown below:

    class A{
     int a=1;
    System.out.println(" a is  " +a);     //giving error ... understandable
    System.out.println();                   // but why error for this..?
     
       void cal(){
           int b=2;
             System.out.println(" b is " +b);   //working fine
                   }
            }
    public class Test {
     
     
        public static void main(String[] args) {
     
        A a =new A();
     
        a.cal();
     
        }
    }

    Why doesn't java allow this? I mean Should i explicitly write a method to display the value of variables of a particular class? OR Do it this way which is as told in java in main()
    A a = new A();
    System.out.println("a is " +a.a);
    a.cal();
    Last edited by rohan22; July 15th, 2011 at 05:54 AM.


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    Default Re: use of System.out.println(""); error....

    The println calls need to be inside of a method or constructor.
    Statements outside of methods are executed when the class is instantiated. They are for defining and initializing variables.

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    Default Re: use of System.out.println(""); error....

    You can do this if you put your printing code inside an initialization block. This will get executed once for every instance, before the constructor runs. For example:
    class A {
        int a = 1;
        {                                            // open initialization block
            System.out.println(" a is  "+a);     
            System.out.println();                  
        }                                            // close initialization block
     
        void cal() {
            int b = 2;
            System.out.println(" b is " + b);   //working fine
        }
    }
    This is not recommended practice unless you have a good reason for doing it, and in my experience, is rarely, if ever necessary.

  4. The Following User Says Thank You to dlorde For This Useful Post:

    derekeverett (July 19th, 2011)

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