Thread: Straight Line programming

I have a statement like this

Stm s = new CompoundStm(new AssignStm("a", new NumExp(6)), new PrintStm(new PairExpList(new NumExp(8), new LastExpList(new IdExp("b")))));

and I have to get the output like this :

System.out.println("The Total Of Statement is : ");
System.out.println("The Max of Print Argument is : ");
System.out.println("The deep of tree is : ");
System.out.println(" That Code is : ");

I was made a several class like this :

public abstract class Stm {}
public class AssignStm extends Stm {
Exp id; String ids;
 
    public AssignStm(String ids,Exp id ){
       this.ids = ids;
       this.id = id;
}}
 
public class CompoundStm extends Stm {
Stm stm1; Stm stm2;
 
    public CompoundStm(Stm stm1,Stm stm2){
       this.stm1 = stm1;
       this.stm2 = stm2;
}}
 
public class PrintStm extends Stm {
LastExpList last; 
PairExpList pair;
 
    public PrintStm(LastExpList last){
    this.last = last;
    }
 
    public PrintStm(PairExpList pair){
    this.pair = pair;
}
 
public abstract class Exp {}
public class EseqExp extends Exp {
    Exp exp;
    Stm stm;
 
    public EseqExp(Stm stm, Exp exp){
        this.stm = stm;
        this.exp = exp;
 
    }
 
}
 
public class IdExp extends Exp {
    String id;
 
    public IdExp(String id){
        this.id= id;
    }   
}
 
public class NumExp extends Exp {
    int num;
 
    public NumExp(int num){
        this.num= num;
    }    
}
 
public class OpExp extends Exp {
    IdExp id; IdExp id1; NumExp num; NumExp num1;
 
    public final static String plus="+";
    public final static String minus="-";
    public final static String kali="*";
    public final static String bagi="/";
 
    public OpExp(NumExp num, String a ,IdExp id1  ){
        this.num= num;
        this.id= id1;
 
    }
 
    public OpExp(IdExp id, String a ,NumExp num  ){
        this.id= id;
        this.num= num;
 
    } 
 
    public OpExp(NumExp num, String a ,NumExp num1  ){
        this.num= num;
        this.num1= num1;
    } 
 
    public OpExp(IdExp id,  String a, IdExp id1 ){
        this.id= id;
        this.id1= id1;
    }    
}
 
public abstract class ExpListParent {
 
}
 
public class LastExpList extends ExpListParent{
    Exp exp;
 
    public LastExpList(Exp exp){
        this.exp = exp;
    }
}
 
public class PairExpList extends ExpListParent{
    Exp exp; LastExpList last;
 
    public PairExpList(Exp exp, LastExpList last){
        this.exp = exp;
        this.last = last;
    }
}

Can anyone get help me to solve this ?
What should I do ?
Thanks a tons before.

from the new stm, I can this :

The Total Of Statement is :
The Max of Print Argument is :
The deep of tree is :
That Code is :

So, if I have statement like this :

Stm s = new CompoundStm(new AssignStm("a", new NumExp(6)),
new PrintStm(new PairExpList(new NumExp(8), new LastExpList(new IdExp("b")))));

The Total Of Statement is : 2
The Max of Print Argument is : 3
The deep of tree is : 5
That Code is : a =6; print(8,b)

I am totally stress...

best regard from Indonesia. Sorry for my bad english

Originally Posted by andbin

Reading the code, I can have a good/valid idea of what that code should "express". In other words, I understand what you would like to do in general.
But the fact is that you must have a clear vision of where these results (2, 3, etc...) should come from!

Take for example the first result "The Total Of Statement is : 2". Why 2? Try to think ....
You have an Stm variable that references a CompoundStm object. Note here, the real object is a CompoundStm but you "see" it only as the more general Stm base type.
Speaking with words, you should say "hey Stm object, give me the number of statements!". The Stm class should declare an abstract method that must be implemented by all Stm concrete subclasses. The implementation in CompoundStm "knows" that, being a compound statement, it has 2 statements.
But note that in CompoundStm the two objects are of type Stm, so theoretically it's possible that a CompoundStm contains in turn other CompoundStm.
So the same request should go to both stm1 and stm2 until you find a "final" statement that doesn't contain other statements.

To be more clear, suppose a method getStatementsCount() in Stm:
- you invoke getStatementsCount() on s (Stm)
- the concrete implementation (CompoundStm) invokes getStatementsCount() on stm1 and then on stm2
- stm1, being a AssignStm, is not a container for other statements, and should return 1 for getStatementsCount()
- stm2, being a PrintStm, is not a container for other statements, and should return 1 for getStatementsCount()
- CompoundStm get 1 and 1, and so should return 2.

I hope to have explained (for my english ) the concept at high level. Try to think about what I said.

Finally, thanks before.
Literally, I,m stiil Confused. But thank you very much.
should I make getStatementsCount() method for each class, and then I compare ?
or just one method in main class ?

what about instanceOf ? can I use this ?