Top 10 Common Technical Interview Questions & Answers

Technical interviews can be challenging, especially during placement drives. To help you ace the technical test and interview rounds, we’ve compiled 10 frequently asked technical questions along with their conceptual explanations. These questions cover fundamental programming concepts and debugging techniques that will enhance your technical knowledge and problem-solving skills.

1. What is the use of an increment or decrement statement in C?

Answer:

In C programming, increment (++) and decrement (–) operators are used to increase or decrease the value of a variable by 1.

• x++ (Post-increment): First, the value is used in the expression, then incremented.
• ++x (Pre-increment): First, the value is incremented, then used in the expression.
• x-- and --x work similarly for decrementing values.

Suggested Visual: A flowchart demonstrating pre-increment and post-increment execution.

2. How do comment symbols help in debugging?

Answer:

Placing comment symbols (/* */ for multi-line and // for single-line comments) around specific parts of a program allows developers to temporarily disable code without deleting it. This technique, known as commenting out, helps isolate problematic code during debugging.

Suggested Visual: A screenshot showing commented-out code in a C program.

3. What is the use of the ‘\0’ character in C?

Answer:

The \0 (null character) is used to indicate the end of a string in C. It helps functions like printf() and strlen() determine where a string terminates.

Suggested Visual: A representation of a C string in memory, showing the null terminator.

4. What is the difference between = and == operators in C?

Answer:

• = is an assignment operator that assigns a value to a variable.
  • Example: x = 10; assigns 10 to x.
• == is a comparison operator that checks equality between two values.
  • Example: if (x == 10) checks if x is equal to 10.

Suggested Visual: A table comparing assignment and comparison operators with examples.

5. Which of the following operators is incorrect in C? (>=, <=, <>, == )

Answer:

The operator <> is incorrect in C. Instead, != should be used to represent the “not equal to” condition.

Suggested Visual: A table listing valid and invalid relational operators in C.

6. Can curly brackets {} enclose a single line of code?

Answer:

Yes, curly brackets {} are generally used to group multiple lines of code. However, they can also be used for a single statement, though it is not necessary. Many developers use curly brackets even for single lines to improve code readability.

Suggested Visual: A side-by-side comparison of single-line if-else statements with and without curly brackets.

7. Can int store the value 32768? Why or why not?

Answer:

No, a standard int can store values from -32768 to 32767 (16-bit systems). To store 32768, you can use:

• long int (if available)
• unsigned int (if negative values are not needed)

Suggested Visual: A table showing data type ranges in C.

8. Can two or more operators (\n and \t) be combined in a single line of code?

Answer:

Yes, multiple escape sequences can be combined in a single statement.
Example:

printf("Hello\n\tWorld");  

This prints “Hello” on one line and “World” indented on the next line.

Suggested Visual: Code snippet output demonstrating \n and \t effects.

9. When is the void keyword used in a function?

Answer:

void is used in function declarations when:

• A function does not return a value. Example: void displayMessage() { printf("Hello, World!"); }
• A function has no parameters. Example: int myFunction(void).

Suggested Visual: A diagram illustrating function return types in C.

10. Write a loop statement that prints the following pattern:

1  
12  
123  
1234  
12345  

Answer:

for (int a = 1; a <= 5; a++) {  
    for (int b = 1; b <= a; b++)  
        printf("%d", b);  
    printf("\n");  
}  

This nested loop constructs the required pattern.

Suggested Visual: Output screenshot showing the printed pattern.

Final Thoughts

These technical questions cover fundamental concepts commonly asked in coding interviews. Practicing such questions will improve your problem-solving skills, logical thinking, and coding efficiency. Keep revising and testing your knowledge with mock interviews and coding exercises.