Which of the following correctly defines a structure in C?

The correct answer is C: struct MyStruct { int a; float b; };. The correct syntax uses the 'struct' keyword followed by the structure name and then the member declarations enclosed in braces.

Which of the following correctly declares a 2D array in C?

The correct answer is A: int arr[3][4];. A 2D array in C is declared using the syntax: datatype arrayName[rows][columns]. So 'int arr[3][4];' creates a 2D array with 3 rows and 4 columns.

What will be the result of executing: int a = 5, b = 10; int *ptr = &a; ptr = &b; printf("%d", *ptr);?

The correct answer is B: 10. ptr is reassigned to point to b. When we dereference ptr using *ptr, we get the value stored at b, which is 10.

What is the size of an integer variable in most modern C compilers?

The correct answer is B: 4 bytes. On most modern 32-bit and 64-bit systems, an int is typically 4 bytes (32 bits). However, the exact size can vary depending on the compiler and system architecture.

What is the difference between structure and union in C?

The correct answer is B: Structure allocates memory to all members; union allocates shared memory. Structure allocates separate memory for each member (total size = sum of all members). Union shares a single memory location among all members (total size = size of largest member). This is a fundamental difference in memory allocation.

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Showing 91–94 of 94 questions

Q.91 Easy Database/SQL

In SQL, what does the GROUP BY clause do?

A Joins multiple tables

B Aggregates rows into groups based on specified columns

C Deletes duplicate records

D Orders results alphabetically

Correct Answer: B. Aggregates rows into groups based on specified columns

Explanation:

GROUP BY groups rows with identical values in specified columns, used with aggregate functions like COUNT(), SUM().

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Q.92 Easy Database/SQL

In a relational database, which normal form eliminates partial dependencies and is considered essential for most practical database designs?

A Second Normal Form (2NF)

B Third Normal Form (3NF)

C Boyce-Codd Normal Form (BCNF)

D Fourth Normal Form (4NF)

Correct Answer: B. Third Normal Form (3NF)

Explanation:

3NF eliminates partial and transitive dependencies, making it the standard for practical database design. BCNF is stricter but 3NF is the most commonly implemented normalization form.

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Q.93 Easy Database/SQL

Which of the following is a characteristic of NoSQL databases that makes them suitable for handling big data in cloud environments?

A Strict ACID compliance across all nodes

B Horizontal scalability and schema-less design

C Requirement for predefined schemas before insertion

D Complex JOIN operations for data retrieval

Correct Answer: B. Horizontal scalability and schema-less design

Explanation:

NoSQL databases like MongoDB and Cassandra are designed for horizontal scaling and flexible schemas, making them ideal for cloud-based big data applications with varying data structures.

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Q.94 Easy Database/SQL

Which of the following represents a vulnerability in SQL query construction that can be exploited through malicious user input, and can be prevented using parameterized queries?

A Buffer overflow attacks

B Cross-site scripting (XSS)

C SQL injection attacks

D Distributed denial of service (DDoS)

Correct Answer: C. SQL injection attacks

Explanation:

SQL injection occurs when untrusted input is concatenated into SQL queries. Parameterized queries/prepared statements separate code from data, preventing attackers from modifying query logic.

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