Computer Knowledge

Programming Fundamentals

2,611 Questions

Programming fundamentals form the core logic of software development and computer science. This includes variable declarations, pointer assignments, loop iterations, and exception handling. These technical topics are regularly tested in computer knowledge and IT officer competitive examinations.

Variables and arraysPointer assignmentsLoop iterationsException handling blocksCompile time errorsFunction references

Programming Fundamentals Questions

Multiple choice

What does the following C-statement declare?

  1. A function that takes an integer pointer as argument and returns an integer

  2. A function that takes an integer pointer as argument and returns an integer pointer

  3. A pointer to a function that takes an integer pointer as argument an returns

  4. A function that takes an integer pointer as argument returns a function pointer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Multiple choice

In a bottom-up evaluation of a syntax directed definition, inherited attributes can

  1. always be evaluated

  2. be evaluated only if the definition is L-attributed

  3. be evaluated only if the definition has synthesized attributes

  4. never be evaluated
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Every S (synthesized) -attributed definitions is L- attributed. So in a bottom-up evaluation of SDD inherited attributes can be evaluated only if the definition has synthesized attributes.

Multiple choice

Which of the following statements is FALSE?

  1. In statically typed languages, each variable in a program has a fixed type

  2. In un-typed languages, values do not have any types

  3. In dynamically typed languages, variables have no types

  4. In all statically typed languages, each variable in a program is associated with values of only a single type during the execution of the program
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

(1) True for statically typed languages where each variable has fixed type. Similarly (4) is also correct. (2) True, in un-typed languages types of values are not defined. But option (3) is false, since in dynamically typed language variables have dynamically changing types but not that they have no type.

Multiple choice

The following program fragment is written in a programming language that allows global variables and does not allow nested declarations of functions. global int i = 100, j = 5; void P(x) { int i = 10; print(x + 10); i = 200; j = 20; print (x); } main() {P(i + j);}

If the programming language uses static scoping and call by need parameter passing mechanism, the values printed by the above program are

  1. 115, 220

  2. 25, 220

  3. 25, 15

  4. 115, 105
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Multiple choice

The following program fragment is written in a programming language that allows global variables and does not allow nested declarations of functions. global int i = 100, j = 5; void P(x) { int i = 10; print(x + 10); i = 200; j = 20; print (x); } main() {P(i + j);}

If the programming language uses dynamic scoping and call by name parameter passing mechanism, the values printed by the above program are

  1. 115, 220

  2. 25, 220

  3. 25, 15

  4. 115, 105
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multiple choice

Which of the following is NOT an advantage of using shared, dynamically linked libraries as opposed to using statically linked libraries?

  1. Smaller sizes of executable files

  2. Lesser overall page fault rate in the system

  3. Faster program startup

  4. Existing programs need not be re-linked to take advantage of newer versions of libraries
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The advantages of shared dynamically linked libraries include. (1) smaller size of executable since less data (2) lesser overall page fault rate. (3) No need for re-linking if newer versions of libraries are there. But since compilation time doesn't include linking so a long linking time required during runtime in DLL' s so slow startup.

Multiple choice

Consider the syntax directed definition shown below, S $\rightarrow$ id : = E {gen (id.place = E.place;);} E $\rightarrow$ E1 + E2 {t = newtemp( ); gen(t = E1.place + E2.place;); E.place = t;} E $\rightarrow$ id {E.place = id.place;}

Here, gen is a function that generates the output code, and newtemp is a function that returns the name of a new temporary variable on every call. Assume that ti's are the temporary variable names generated by newtemp. For the statement 'X : = Y + Z', the 3-address code sequence generated by this definition is

  1. X = Y + Z

  2. t1 = Y + Z; X = t1

  3. t1 = Y; t2 = t1 + Z; X = t2

  4. t1 = Y; t2 = Z; t3 = t1 + t2; X = t3
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Multiple choice

Which of the following are true? I. A programming language which does not permit global variables of any kind and has no nesting of procedures/functions, but permits recursion can be implemented with static storage allocation II. Multi-level access link (or display) arrangement is needed to arrange activation records only if the programming language being implemented has nesting of procedures/functions III. Recursion in programming languages cannot be implemented with dynamic storage allocation IV. Nesting procedures/functions and recursion require a dynamic heap allocation scheme and cannot be implemented with a stack-based allocation scheme for activation records V. Programming languages which permit a function to return a function as its result cannot be implemented with a stack-based storage allocation scheme for activation records

  1. II and V only

  2. I, III and IV only

  3. I, II and V only

  4. II, III and V only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Multiple choice

Consider the following C code segment.

for (i - 0, i < n; i++) {
  for (j = 0; j < n; j++) {
    if (i % 2) {
      x += (4 * j + 5 * i);
      y += (7 + 4 * j);
    }
  }
}

Which one of the following is false?

  1. The code contains loop invariant computation

  2. There is scope of common sub-expression elimination in this code

  3. There is scope of strength reduction in this code

  4. There is scope of dead code elimination in this code
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All the statements are true except option (4) since there is no dead code to get eliminated

Multiple choice

Consider the following code written in a pass-by-reference language like FORTRAN and these statements about the code.

S1: The compiler will generate code to allocate a temporary nameless cell, initialize it to 13, and pass the address of the cell swap S2: On execution the code will generate a runtime error on line L1 S3: On execution the code will generate a runtime error on line L2 S4: The program will print 13 and 8 S5: The program will print 13 and - 2 Exactly the following set of statement(s) is correct:

  1. S1 and S2

  2. S1 and S4

  3. S3

  4. S1 and S5
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Multiple choice

To evaluate an expression without any embedded function calls

  1. One stack is enough

  2. Two stack are needed

  3. As many stacks as the height of the expression tree are needed

  4. A Turning machine is needed in the general case
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

To evaluate an expression we need only 1 stack in which the operands & operators are pushed into, & then evaluated using pop operations.

Multiple choice

Consider the following code fragment: if (fork()==0 {a = a + 5; print f (%d,%/na, and a);} else {a − 5; print f (%d,%d/n,a,&a);} Let u, v be the values printed by the parent process, and x,y be the values printed by the child process. Which one of the following is TRUE?

  1. u = x + 10 and v = y
  2. u = x + 10 and v $\ne$ y

  3. u + 10= x and v = y
  4. u + 10 = x and v $\ne$ y
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Initial value of a is 10 and its address and the value of 'a' would be different for both the parent and child processes. So, (1) and (2) are incorrect. Also, parent process executes a = a − 5 = 5 = u and child executes a = a + 5 = 15 = x. Therefore, u + 10 = x.

Multiple choice

The atomic fetch-and-set x, y instruction unconditionally sets the memory location x to 1 and fetches the old value of x n y without allowing any intervening access to the memory location x. consider the following implementation of P and V functions on a binary semaphore S. void P (binary_semaphore *s) { unsigned y; unsigned *x = &(s->value); do { fetch-and-set x, y; } while (y); } void V (binary_semaphore *s) { S ->value = 0; } Which one of the following is true? ( Which one of the following is true?

  1. The implementation may not work if context switching is disabled in P

  2. Instead of using fetch-and -set, a pair of normal load/store can be used

  3. The implementation of V is wrong

  4. The code does not implement a binary semaphore
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If there are more than two processes and context & switching processes is disabled in P then this implementation doesn't work properly and can't synchronize the processes.