Urgent solutions needed

Problem 1 [9pt] Consider the following C program: int SumOfSquares(int n) { if (n <= 0) return 0; else return n*n+SumOfSquares(n-1); } a) (5pt) Write down a tail recursive implementation of function SumOfSquares in C language. You can use helper function in your solution. b) (4pt) An “optimizing” compiler will often be able to generate efficient code for recursive functions when they are tail-recursive. Refer to activation record, briefly explain how a compiler may “reuse” the same activation record for your solution in a). Problem 2 [6pt] In early implementations of Fortran language, a compiler may choose to use static allocation (i.e., allocation in the static area) for local variables and parameters, effectively arranging for the variables of different invocations to share the same locations, and thereby avoiding any run-time overhead for creation and destruction of stack frames. However, such an implementation changes the meaning of recursive function calls. Write down a simple example and explain how its meaning changes under the “Fortran” semantics as stated above, compared with standard semantics found in language like C, Python, Java. Problem 3 [6pt] Suppose as a language designer, you plan to implement a feature called “output-only” parameters. The expected semantics is that all output-only parameters are uninitialized when the callee starts execution; they can be used (both read and write) as other kinds of parameters within the callee; finally, the corresponding actual parameter in the caller is updated to the final values of the “output-only” parameters. Briefly describe one possible implementation of such “output-only” parameters. Problem 4 [16pt] Consider the following C-like program. Write down what will be printed out when the parameters are passed (1) by value, (2) by reference, (3) by value return and (4) by name. For each answer, briefly explain how did you derive it. Answers without a brief explanation will receive ZERO points. int x=5, y=6; void foo(int a, int b) { x = a+b; b = a+a; } main () { foo(x,y); print x, y; } Problem 5 [13pt] Consider the following code snippet with exceptions. Note that the main function calls foo in the nested try block. 1/2void foo () { try { throw new Exception1(); print ("A"); throw new Exception2(); print ("B"); } catch(Exception1 e1) { print "handler1"; } print ("C"); throw new Exception2(); } void main () { try { try { foo(); print ("D"); } catch(Exception1 e1) { print "handler2"; } } catch(Exception2 e2) { print "handler3"; } } a) (6pt) Write down what will be printed out by the program and briefly justify your answer. b) (7pt) Instead of the “replacement” semantics of exception handling used in modern languages (i.e., the semantics introduced in lecture), a very early design of exception handling introduced in the PL/I language uses a “binding” semantics. In particular, the design dynamically tracks a sequence of “catch” blocks that are currently active; a catch block is active whenever the corresponding try block is active. Moreover, whenever an exception is thrown, the sequence of active “catch” blocks will be traversed (in a first-in-last-out manner) to find a matching handler. Furthermore, execution will resume at the statement following the one that throws exception, rather than the next statement after the matching “catch” block as we have seen in the “replacement” semantics. Write down what will be printed out by the program if the language uses the “binding” semantics, and briefly justify your answer.