Question

(17) (1 mark) What is the static parent of a subprogram? (18) (1 mark) What is a formal parameter? (19) (3 marks) Consider the following program, written in a C-like lan- guage int x void f(int a) {а- а+2; х %3D х+1;} void main x 1 f(x); printf("x= d\n",x); What value ot xwill be printed by the main program under each of the tollowing conditions? Imagine that tformal parameter a of function fis being passed: i by value ii. by value-result ii. by reference (20) (2 marks) Consider the C function int myFun(a: int; b: char){ xy float; Drawthe layout of the activationrecordforthis function. The ordering ot elements is important- assume that the stack grows upwards. (21) (1mark) What is the advantage ofseparate compilation over indepen dant compilation? (22) (1 mark) A static chain links a set of activation record instances to- gether. How are these instances related? (23) (1mark) Why dothe actual parameters appear in an activation record below (that is, they are pushed onto the stack betore) the local vari- ables?

Answer 1

17.what is the static parent of a subprogram?
ANS: Static chains are primary method of implementing accesses to non-local variables in static-scoped languages with nested subprogram. Static chain is a chain of static links that connects certain activation record instances. The static chain from an activation record instance connect it to all of its static ancestors. The static link in an activation record instance for subprogram A points to one of the activation record instances of A's static Parent.

18.what is a formal parameter?
The identifier used in a method to stand for the value that is passed into the method by a caller.

19. int x;
void f(int a){a=a+2; x=x+1;}
void main(){
   x=1;
   f(x); printf("x=%\n",x)
}
what value of x will be printed by the main program under each of the following conditions?Imagine that formal parameter a of function f is being passed

ANS:

by value: x=1

by value result: x=3

by reference: x=2