What will be the output of: char str[] = "Hello"; printf("%c", str[1]);?

The correct answer is B: e. Array indexing in C starts from 0. str[0]='H', str[1]='e', str[2]='l', str[3]='l', str[4]='o', str[5]='\0'. Therefore, str[1] is 'e'.

Consider: int *ptr; int arr[] = {1,2,3}; ptr = arr; What is ptr[1]?

The correct answer is B: 2. When ptr points to the array arr, ptr[1] is equivalent to *(ptr+1), which accesses the second element of the array, which is 2.

Which header file is required to use the printf() function?

The correct answer is B: #include . The stdio.h (Standard Input Output) header file contains declarations for printf(), scanf(), and other input/output functions. It is essential for console I/O operations.

Which of the following correctly initializes a 2D array?

The correct answer is C: Both A and B. Both syntaxes are correct. C allows initializing 2D arrays with or without explicit braces for each row.

What is the scope of a variable declared inside a function in C?

The correct answer is B: Local/Function scope. Variables declared inside a function have local scope (also called function scope). They are only accessible within that function and are destroyed when the function returns.

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Database/SQL

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All C Programming 200 Database/SQL 100

Q.11 Medium Database/SQL

Which normalization form eliminates all non-key dependencies?

A 1NF

B 2NF

C 3NF

D 4NF

Correct Answer: C. 3NF

EXPLANATION

3NF (Third Normal Form) ensures all non-key attributes depend only on the primary key, eliminating transitive dependencies.

Test

Q.12 Medium Database/SQL

What is the correct order of operations for the Big O notation from least to most complex?

A O(1) < O(n) < O(n²) < O(2ⁿ) < O(n!)

B O(n!) < O(2ⁿ) < O(n²) < O(n) < O(1)

C O(n) < O(1) < O(n²) < O(2ⁿ) < O(n!)

D O(log n) > O(1) > O(n) > O(n²)

Correct Answer: A. O(1) < O(n) < O(n²) < O(2ⁿ) < O(n!)

EXPLANATION

Constant O(1) is fastest, followed by logarithmic O(log n), linear O(n), quadratic O(n²), exponential O(2ⁿ), and factorial O(n!) which is slowest.

Test

Q.13 Medium Database/SQL

In operating systems, what is a deadlock?

A When a process terminates unexpectedly

B When two or more processes are blocked, each waiting for resources held by the other

C When memory is exhausted

D When the CPU stops functioning

Correct Answer: B. When two or more processes are blocked, each waiting for resources held by the other

EXPLANATION

Deadlock is a situation where multiple processes cannot proceed because each holds resources needed by others, creating a circular wait condition.

Test

Q.14 Medium Database/SQL

What is the primary advantage of using MongoDB (NoSQL) over traditional relational databases?

A It provides ACID compliance on all operations

B It has flexible schema that accommodates unstructured data and horizontal scalability

C It uses SQL for all queries

D It requires less storage space

Correct Answer: B. It has flexible schema that accommodates unstructured data and horizontal scalability

EXPLANATION

MongoDB's document-based model allows flexible schemas for unstructured data and supports horizontal scaling, unlike rigid relational schemas.

Test

Q.15 Medium Database/SQL

In machine learning, what does overfitting mean?

A The model is too simple to learn patterns

B The model learns training data too well, including noise, reducing generalization to new data

C The model has too many layers

D The model requires more training data

Correct Answer: B. The model learns training data too well, including noise, reducing generalization to new data

EXPLANATION

Overfitting occurs when a model learns the training data including its noise and irregularities, performing poorly on unseen test data.

Test

Q.16 Medium Database/SQL

Which of the following best describes a graph data structure with no cycles?

A Directed Graph

B Tree

C Complete Graph

D Bipartite Graph

Correct Answer: B. Tree

EXPLANATION

A tree is a special case of a graph with no cycles. It has n nodes and n-1 edges, forming a hierarchical structure.

Test

Q.17 Medium Database/SQL

Which cloud service model provides pre-configured application environments?

A IaaS (Infrastructure as a Service)

B PaaS (Platform as a Service)

C SaaS (Software as a Service)

D DaaS (Database as a Service)

Correct Answer: B. PaaS (Platform as a Service)

EXPLANATION

PaaS provides a complete development and deployment environment in the cloud, including pre-configured tools and frameworks.

Test

Q.18 Medium Database/SQL

What does ACID compliance in databases ensure?

A Data is always encrypted

B Atomicity, Consistency, Isolation, and Durability of transactions

C Automatic data compression

D Asynchronous data backup

Correct Answer: B. Atomicity, Consistency, Isolation, and Durability of transactions

EXPLANATION

ACID is a fundamental database property: Atomicity (all-or-nothing), Consistency (valid state), Isolation (concurrent independence), Durability (permanent after commit).

Test

Q.19 Medium Database/SQL

Which sorting algorithm has the best average-case time complexity for randomly distributed data?

A Bubble Sort - O(n²)

B Quick Sort - O(n log n)

C Insertion Sort - O(n²)

D Selection Sort - O(n²)

Correct Answer: B. Quick Sort - O(n log n)

EXPLANATION

Quick Sort has O(n log n) average-case complexity, making it most efficient for random data. Though worst-case is O(n²), randomized pivot selection minimizes this risk.

Test

Q.20 Medium Database/SQL

Which of the following is a correct SQL syntax for creating an index on multiple columns?

A CREATE INDEX idx_name ON table_name (col1, col2);

B CREATE UNIQUE INDEX idx_name ON table_name (col1, col2);

C CREATE INDEX idx_name ON table_name COLUMNS (col1, col2);

D Both A and B are correct

Correct Answer: D. Both A and B are correct

EXPLANATION

Both syntaxes are valid in SQL. The first creates a composite index, while the second creates a unique composite index.

Test

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