Question 10619 – GATE 1987

Var x, y:interger; 
procedure P(n:interger);
begin
     x:=(n+2)/(n-3);
end;

procedure Q 
Var x, y:interger;
begin   
    x:=3;
    y:=4; 
    P(y);
    Write(x)                                __(1)
end;
 
begin
    x:=7;
    y:=8;
    Q; 
Write(x);                                   __(2) 
end.

First procedure Q is called from the main procedure. Q has local variables x and y with values 3 and 4 respectively. This local variable y (value 4) is being parsed to procedure P during call, and received in local variable n inside procedure P. Now as P does not have any local definition for variable x, it will assign the evaluated value of (n+2)/(n-3), i.e., (4+2)/(4-3)=6 to the global variable x, which was previously 7. After the call of procedure P, procedure Q writes the value of local variable x which is still 3. Lastly, the main procedure writes the value of global variable x, which has been changed to 6 inside procedure P. So, the output will be 3, 6.