GATE CSE 2001 | Question: 2.19

Question

Consider the following program

Program P2
    var n : int;
    
    procedure W(var x : int)
    begin
        x = x + 1;
        print x;
    end

    procedure D
    begin
        var n : int;
        n = 3;
        W(n);
    end

    begin    \\begin P2
        n=10;
        D;
    end

If the language has dynamic scooping and parameters are passed by reference, what will be printed by the program?

• A. 10
• B. 11
• C. 3
• D. None of the above

Answer 1

answer is D.

here, because of dynamic scoping the value of n passed in w(n) will be n=3.

therefore o/p will be 4, which is not in any option.

Comments

dynamic scoping part is understood by me the answer will be 4..but does parameters are passed by reference mean the below when converted to C language.

 int n;

 W(int *x) {*x = *x + 1; print *x;}     

D(){int n; n = 3; W(&n); }

main(){n=10; D(); }

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You are correct  Nitika Gupta.Internally how it will change it does not matter,What matters in the actual value of n will be changed by which is passed by D to W 

Also, in the answer it says that

 here, because of dynamic scoping the value of n passed in w(n) will be n=3.

I dont think dynamic scoping will have any role here,because as long as we have local variable(x),it will be used.Scoping comes into picture,when variable getting used is not defined in the scope of the function which is using it.

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Even if you run it in C, the answer will be 4. C uses static scoping if anyone wants to check.

Answer 2

It print 4 , which is not in option,

So correct option is D