Computer Science – Principles of Programming Languages

If the postfix equivalent of the statement
if c then x else y is cxy#, then the postfix form amn+mn-ab-#ba-#

A recursive function f , is defined as follows:
f (n) = 2, if n = 0
= m, if n = 1
= 2xf (n-1) + 4xf (n-2) , if n >= 2
if the value of f (f) is 88 then the value of m is

Consider the FORTRAN statement – DO5I = 1, 10
To recognize Do as a keyword, the compiler (lexical analyzer) has to scan

Use of recursion

A program has 100 instructions and another program (for the same problem) has 200
instructions. Which of the following comment logically follows?

The conditional expansion facility of macro processors is provided to

Which of the following languages is case-sensitive (i.e., IF is not same as if)?

Val is a well known

Consider the following pseudo-Pascal function
function fibo (n : integer) : integer ;
begin
if (n = 0) then fibo := 0
else if (n = 1) then fibo := 1
else fibo := fibo (n-1) + fibo (n-2)
end
If fibo (5) is the function call, fibo (1) will be used

An ordinary calculator treats all operators

In which of the following parameter passing mechanism, the actual argument has to be a variable?

Which of the following class of statements usually produce no object code when compiled?

The principle that a function can always be replaced by its value (irrespective of the context, without changing the meaning is called

Programming languages offer features to write functions to

The following pseudo-Pascal procedure
Procedure palin ;
var c : char ;
begin
read (c) ;
if NOT eoln then palin ;
write (c) ;
end
can be used to

In a certain language, the expression 5-3+2 x 4+1, evaluates to 0. Which of the following conclusions about the precedence and associativity of the operators +, -, * are correct ?

The output of the following pseudo-Pascal program is
var a : integer;
procedure p;
begin
a := 2; write (a)
end
begin
a := 1; p; write (a)
end

Which of the following comparisons between static and dynamic type checking is incroorect?

The period of time between an allocation and its subsequent disposal is called

Consider the following pseudo-Pascal program.
procedure A;
x,y : integer ;
procedure B;
x,z : real ;
statement 1
end B;
procedure C;
i : integer;
statement 2
end C;
end A;
The variables accessible in statement 1 and statement 2 are

Consider the following sequence of statements
statement 1: A := B+c
statement 2: D := A+c
statement 3: E := A+B
statement 4: G := D+E
statement 5: H := E+A
statement 6: I := H+G
which of the statements can be executed in parallel ?

If instruction are executed in parallel, whenever the required operands are available, then the execution time of the previous problem is logically same as that of sequentially executing

Aliasing is a situation where

Consider the following variant record declaration in pseudo-Pascal.
type abc = record
x : integer ;
case y : integer of
1 : (m : integer, n : real);
2 : (e, f : integer) ;
end
suppose a program uses an array of ‘p’ such records. Integer need 2 bytes of storage and real r bytes. If the array occupies 480 bytes, the value of p will be

A recursive function f (x) , is defined as follows:
if (x>100)
return (x-10)
else return (f(f(x+11)))
For which of the following values of x, f(x) = 91?

English language uses full stop as a sentence

In a hypothetical language, all operators have equal precedence and associate to the left, In this language, the expression 5 x 3 – 2 – 1 x 2 evaluates to

Overloading is

You are asked to use a computer to solve a problem given to you. How fast the computer solves your problem, depends on the

Which of the following is a dangling reference ?

Heap allocation is required for languages that

Jensen’s device makes explicit use of the property of

For which of the following applications will you prefer a co-routine to a subroutine?

Binding (of an identifier to a value) can occur while

COMMON feature of FORTRAN is not found in most of the languages that followed it because

Consider the following program fragment
procedure exchange (A: integer, B: integer)
temp : integer;
begin
temp := A; A := B; B := temp
end;
begin
M := 2; X[M]); write (M, x[2]);
end
If the parameters are passed by value, the output will be

4, 2 will be the output of the previous question if the parameters are passed by

If the parameters are passed by name, the output will be

Choose the correct remarks that are based on the following pseudo-Pascal function.
function doit (x, y : integer): integer;
begin
if(x = 0) then doit := y
else if (y = 0) then doit := x
else doit := doit (x-1, y-1)
end

Which of the following can be correctly identified to be Pascal tokens without look-ahead scanning?

Consider the following pseudo-Pascal program (assume(*starts a comment and*) ends a comment)
procedure doit (A, B, C) : integer;
begin
B := B-2; C := A+c (*; write (A)
end
If this program prints 16, then A, B, C should have been declared as

If the comment is removed in the previous in the previous problem, it will print 18,8, if the parameter declaration is

The vernacular language English can’t be used as a Computer Programming language because.

Choose the correct statements.

Binding cannot be done

The target of an assignment statement should be

Which of the following problem are iterative, rather than recursive in nature?

BNF is a meta-language for

The basic difference between a procedural language and an applicative language is that the

The output of the following Pascal program is
program x;
var char, real : integer;
false : boolean:
begin
char := 1; real := char; false := (char = real);
if (false = ture) then writeln (‘Don’t Worry’)
else writeln (‘Be Happy’)
end

This language is as powerful as

One of the four instructions is not needed That is

The program
clr C; clr B;
while (A not 0)
do
inc C; dec A;)
end;
while (C not 0)
do
inc A; inc B; dec C;
end

The program
clr C;
while A not 0
do
clr x;
while (B not 0)
do
inc C; inc x; inc B;
end;
while (x not 0)
do
inc B; dec x;
end;
dec A;
end

If we add one more instruction cpy x, y – which copies the contents of x to y, then the following program,
clr C; cpy A, x;
while(x not 0)
do
cpy x, y;
while (y not 0)
do
inc C; dec Y;
end;
dec x;
end

The following program
cpy A, x; clr C;
while (x not 0)
do
inv C; dec x;
end

The following program
cpy A, x;
while (x not 0)
do
inv M; clr x;
end;
cpy A, x; inv x;
while(x not 0)
do
inc M; clr x;
end

In which of the following cases, is it possible to obtain different results for call-by-reference and call-bu-name parameter passing?

If the language uses static scope rules, the output will be

If the language uses dynamic scope rules, the output will be

What will the following function compute?
function what (x, n : integer) : integer ;
var
value : integer;
begin
value := 1;
if (n > 0) then
begin
if (n mod 2 = 1) then
value := value*x;
value := value*what (x*x, n div 2);
end;
what := value;
end;

An array A consists of n integers in locations A[0]m A[1]m . . . A[n-1]. It is a required to shift the elements of the array cyclically to the let by k places, where 1 ≤ k ≤ n – 1 . An incomplete algorithm for doing this is linear time, without using another array is given below. Complete the algorithm by filling in the blanks. Assume all variables are suitably declared.
min := n; i := 0;
while (_______) do
begin
temp := A [i] ; j ;= i;
while (_______) do
begin
A[j] := ______; j := (j+k) mod n;
if (j < min) then min := j; end; A[(n+i-k) mod n] := ________; i := _________; end;

If static scoping is used by all variable, the output will be

If dynamic scoping is used by all variable, the output will be

Consider the recursive function
function fib(n : integer) : integer;
begin
if (n = 0) or (n = 1) then fib := 1
else fib := fib(n-1) + fib (n-2)
end;
The function is run on a computer with a stack of size 64 bytes. If only the return address and parameter are passed to the stack and they need two bytes each, estimate the maximum value of n for which the stack does not overflow.

FORTRAN does not permit recursion because

A data driven machine is one that executes an instruction if the needed data is available. The physical ordering of the code listing does not dictate the course of execution. Consider the following pseudo-code.
(A) Multiply E by 0.5 to get F (B) Add A and B to get E
(C) Add B with 0.5 to get D (D) Add E and F to get G
(E) Add A with 10.5 to get C
Assume, A, B, C are already assigned values and the desired output is G.
Which of the following sequence of execution is valid?

In the previous question in how many different ways can the 5 instructions be sequenced ?

In a demand-driven machine, an instruction is not execued until its output is needed.For the previous question, in what order will the instructions be sequenced ?

Choose the correct statements.

The following is an incomplete pseudo-Pascal function to convert a given decimal integer (in the range -8 to 7) into a binary integer in 2’s complement form. Determine the expressions that complete the program.
function TWOCOMP (N : integer) : Integer;
var
REM, EXPO, BINARY : integer ;
begin
if(n ≥ – 8) and (N ≤ 7) then
begin
if N N 0 then
N := . . . ;
BINARY := 0; EXPO := 1;
while N <> do
begin
REM := N mod 2;
BINARY := BINARY + . . . * EXPO;
EXPO := EXPO*10;
N := . . . ;
end;
TWOCOMP := BINARY
end
end;

In the following pseudo-pascal program segment, the Value x, after the execution of the program is
X := -10 ;
Y := 20 ;
if X>Y
then
if X<0
then X := abs (X)
else X := 2*x;

Consider the following macro definition.
macro Add x, y
Load y
Mul x
Store y
end macro
x and y are

Which of the following strings can definitely be said to be tokens without looking at the next input character while compiling a pascal program
I, begin II, program III. <>

Assume X and y are non-zero positive integers. The following pseudo-Pascal program
while x <> y do
if X > y then x := x-y
else y := y-x :
write (X) ;

The value of x printed by the following pseudo-Pascal program is
program COMPUTE (input, output) ;
var
X : integer ;
Procedure FIND (X : real) ;
begin
X := sqrt (X) ;
end;
begin
X := 2 ; FIND(X) ; writeln (X)
end.

A language with string manipulation facilities uses the following operations.
head (s) – returns the first character of string S.
tail (s) – returns all but the first character of string S.
concat (s1, s2) concat (head (s) , head (tail (tail (s)))) , where s is acbc, is

Which of the following statements are true?
I. AS the number of entries in the hash table increases, the number of collisions increases.
II. Recursive programs are efficient.
III. The worst case complexity of Quick sort is O (

n²

)
IV. Binary search using a linear linked list is efficient.

Consider the following high level program segment.
var
A, B, W, X, Y : unsigned byte;
begin
x := A+B;
Y := abs(A-B) ;
W := A-B;
Z := A*B;
end
Assuming integer occupies 2 bytes and the initial values of A and B are 5CH and 92H respectively, the final values of W, X, Y and Z will be

Consider the following pseudo-Pascal function, where A and B are non-zero positive integers. What is the value of GET (3,2)?
function GET (A, B : integer) : integer;
begin
if B = 0
then
GET := 1
else if A < B then GET := 0 else GET := GET (A-1,B) + GET (A-1,B-1) end;

A variant record in Pascal is defined as
type varirec = record
number: integer;
case (varl, Var2) of
Var1 : (x, y : integer) ;
Var2 : (p, q : real)
end
end
suppose an arry of 100 such records was declared on a machine, which uses 4 bytes for an integer and 8 bytes for a real. How much space would the compiler have to reserve for the array?

Consider the assignment statement
var1 = var1 + var2 ;
The sequence of notations that correctly reflects the usage of the variable var1 is

Which of the following sequences (for a particular variable) is harmless but suspicious?

Which of the following sequence (for a particular variable) are probably bugs?

In addition to the above notations let us use the notation-X, where X is one of D, K or U, to mean that nothing of interest (concerning the variable under consideration ) happened to the variable. Which of the following situations are probably anomalous?

Vernacular languages (like English) and programming languages have a lot of similarities. In a broad sense, the nouns and verbs are comparable to

Consider the following C program.
#include “stdio.h”
main ( )
{
enum boolean {true, false};
enum boolean a, b, c;
a = b = true;
c (a==b);
if (c == a)
printf (“TRUE”);
else
printf (“FALSE”);
}
The output of the above program will be