What is the size of int data type in a 32-bit system?

The correct answer is B: 4 bytes. In a 32-bit system, the int data type typically occupies 4 bytes (32 bits). This is the standard size for integer types on most 32-bit architectures.

Which of the following is NOT a valid identifier in C?

The correct answer is B: 123_variable. In C, an identifier cannot start with a digit. It must start with a letter (a-z, A-Z) or underscore (_). Option B violates this rule by starting with a digit.

What will be the output of: printf("%d", 5 + 3 * 2);?

The correct answer is B: 11. Operator precedence: multiplication (*) is performed before addition (+). So: 3 * 2 = 6, then 5 + 6 = 11.

What will be the result of: 5 % 2 * 3 / 2?

The correct answer is B: 2. Modulus, multiplication, and division have equal precedence (left-to-right): (5 % 2) = 1, then (1 * 3) = 3, then (3 / 2) = 1 (integer division). Answer is 1, not 2. Correction: 1 is correct.

What is the primary difference between malloc() and calloc() functions in C?

The correct answer is B: malloc() doesn't initialize memory, while calloc() initializes it to zero. Both malloc() and calloc() allocate dynamic memory. The key difference is that malloc() allocates uninitialized memory (contains garbage values), while calloc() allocates memory and initializes all bytes to zero. calloc() also takes two arguments (number of elements and size of each element), while

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Difficulty: All Easy Medium Hard 1–10 of 150

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All C Programming 200 Database/SQL 100

Q.1 Medium Database/SQL

In the context of distributed databases, which consistency model is used by most cloud-native databases like DynamoDB and offers eventual consistency?

A Strong Consistency

B Causal Consistency

C Eventual Consistency

D Linearizability

Correct Answer: C. Eventual Consistency

EXPLANATION

Cloud-native NoSQL databases prioritize availability and partition tolerance (CAP theorem), implementing eventual consistency to handle distributed system challenges while maintaining horizontal scalability.

Test

Q.2 Medium Database/SQL

Which of the following SQL query optimization techniques is most effective when dealing with large fact tables in a data warehouse environment?

A Using UNION instead of UNION ALL

B Materialized views and denormalization

C Increasing the number of JOINs in queries

D Using correlated subqueries for filtering

Correct Answer: B. Materialized views and denormalization

EXPLANATION

Data warehouses use materialized views to pre-aggregate data and strategic denormalization for faster analytical queries. These techniques significantly improve performance on large fact tables.

Test

Q.3 Medium Database/SQL

In database indexing, which type of index structure provides the best average-case performance for range queries in modern database systems?

A Hash Index

B B+ Tree Index

C Bitmap Index

D Full-text Index

Correct Answer: B. B+ Tree Index

EXPLANATION

B+ Tree indexes maintain sorted order and support efficient range queries, point queries, and prefix searches. Hash indexes are faster for exact matches but cannot handle range queries efficiently.

Test

Q.4 Medium Database/SQL

What is the primary difference between supervised and unsupervised machine learning?

A Supervised uses labeled data; unsupervised uses unlabeled data

B Unsupervised is faster than supervised

C Supervised cannot predict outcomes

D Unsupervised requires human supervision

Correct Answer: A. Supervised uses labeled data; unsupervised uses unlabeled data

EXPLANATION

Supervised learning trains on labeled data (features + targets); unsupervised finds patterns in unlabeled data without predefined outputs.

Test

Q.5 Medium Database/SQL

In cybersecurity, what is SQL injection attack?

A Inserting legitimate SQL into database

B Malicious SQL code injected into input fields to manipulate database queries

C A method to optimize SQL performance

D Splitting SQL statements across multiple lines

Correct Answer: B. Malicious SQL code injected into input fields to manipulate database queries

EXPLANATION

SQL injection exploits vulnerable input handling to execute unintended SQL commands, potentially exposing or modifying data.

Test

Q.6 Medium Database/SQL

What does normalization in machine learning context primarily aim to achieve?

A Reduce features to 2D

B Scale features to similar ranges to improve model performance

C Remove all outliers

D Increase dataset size

Correct Answer: B. Scale features to similar ranges to improve model performance

EXPLANATION

Normalization scales features (e.g., 0-1 range) preventing features with larger scales from dominating model training.

Test

Q.7 Medium Database/SQL

In graph algorithms, which algorithm finds the shortest path in weighted graphs?

A DFS

B BFS

C Dijkstra's algorithm

D Topological sort

Correct Answer: C. Dijkstra's algorithm

EXPLANATION

Dijkstra's algorithm efficiently finds shortest paths from a source node to all other nodes in weighted graphs with non-negative weights.

Test

Q.8 Medium Database/SQL

What is the difference between DELETE and TRUNCATE in SQL?

A DELETE is faster than TRUNCATE

B TRUNCATE is DDL; DELETE is DML and is slower but can be rolled back

C TRUNCATE cannot be rolled back while DELETE can

D Both have identical functionality

Correct Answer: B. TRUNCATE is DDL; DELETE is DML and is slower but can be rolled back

EXPLANATION

TRUNCATE is DDL (immediate, cannot be rolled back in most databases), DELETE is DML (slower, can be rolled back).

Test

Q.9 Medium Database/SQL

In cloud computing, which service model allows customers to run their own applications but not manage infrastructure?

A IaaS

B PaaS

C SaaS

D DBaaS

Correct Answer: B. PaaS

EXPLANATION

PaaS (Platform as a Service) provides a platform to develop and deploy applications without managing underlying infrastructure.

Test

Q.10 Medium Database/SQL

What is the time complexity of quicksort algorithm in the worst case?

A O(n log n)

B O(n²)

C O(n)

D O(log n)

Correct Answer: B. O(n²)

EXPLANATION

Quicksort's worst-case complexity is O(n²) when pivot selection is poor, though average case is O(n log n).

Test

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