GATE CSE 2000 | Question: 18

Question

Consider the following program  is  pseudo-Pascal syntax

program main;
    var x: integer;  
    procedure Q (z: integer);
    begin     
        z := z+x; 
        writeln(z); 
    end; 
    procedure P (y: integer);
    var x: integer;
    begin     
        x := y+2;       
        Q(x);     
        writeln(x); 
    end  
begin  
    x := 5; 
    P(x); 
    Q(x); 
    writeln(x);
end

What is the output of the program when

1. the parameter passing mechanism is call-by-value and the scope rule is static scoping?  
2. the parameter passing mechanism is call-by-reference and the scope rule is dynamic scoping?

Comments

can someone explain the part b how does it works.

Answer 1

  A) Call By Value : 12 7 10 5  B) Call By Reference : 14 14 10 10

Comments

Call by reference result should be: 14 14 10 10, because procedure P has its own local x which gets changed on calling it, there is no assignment of y therefore, it will not change the value of global x.

Answer 2

COLL BY VALUE; 12,7,10,5