Computer Knowledge

Programming Fundamentals

2,381 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

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

Given two arrays of numbers a1,..........., an and b1,............, bn where each number is 0 or 1, the fastest algorithm to find the largest span (i, j ) such that ai + ai+1 + .........+ aj = bi + bi + 1 +...........+ bj or report that there is not such span,
  1. Takes $\Theta$(3n) and $\Omega$(2n) time if hashing is permitted
  2. Takes $\Theta$(n3) and $\Omega$ (n2.5) time in the key comparison model
  3. Takes $\Theta$(n3) time and space
  4. Takes $\Theta$($\sqrt{n}$) time only if the sum of the 2n elements is an even number
Reveal answer Fill a bubble to check yourself
C 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.

Multiple choice

Which one is wrong with respect to variable name in C language?

  1. Variable name should start with alphabet.

  2. Variable name contains the space.

  3. Variable name should be different from the keywords.

  4. Variable name contains underscore(_).
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Space is not allowed in variable name. For example, RollNum is valid and Roll Num is invalid variable name.

Multiple choice

Characteristics of variable in C language are:

  1. value and types of variable

  2. name and location in the memory

  3. its value can change during execution.

  4. all of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

All of these are the characteristics of Variable. Variables must have its name, data type and value. Without data type variables cannot be declared. Variables also have some location in memory. And variables' value can be changed during the execution of a program.

Multiple choice

Let the clock cycles required for various operations be as follows: Register to/from memory transfer: 3 clock cycles Add with both operand in register: 1 clock cycle Instruction fetch and decode: 2 clock cycles per word

The total number of clock cycles required to execute the program, is

  1. 29

  2. 24

  3. 23

  4. 20
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The clock cycles are per block; if an instruction size is 2 then it requires twice no. of clock cycles.

So answer is (2). 

Multiple choice

A simple two-pass assembler does which of the following the first pass?

  1. <font size="2">I</font>t allocates space for the literals.

  2. <font size="2">I</font>t compute<font size="2">s</font> the total length of the program.

  3. <font size="2">I</font>t builds the symbol table for the symbols and their value.

  4. <font size="2">A</font>ll of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The first pass of a two-pass assembler performs three key tasks: allocating space for literals/pool table, computing the total program length (for address calculation), and building the symbol table with symbol addresses. All options are correct.

Multiple choice

Identify the odd one out.

  1. Global common subexpression

  2. Copy propagation

  3. Register allocation

  4. Code motion
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

a, b and d are ways of code optimization, register allocation happens in code generation stage, so the option c is the odd one.