C# MCQ Question and Answer for Beginner

Which of the following is NOT a valid variable name in C#?

• a) myVariable
• b) number1
• c) @data
• d) 1stNumber (Invalid: cannot start with a number)

What does the Console.WriteLine() method do?

• a) Reads input from the keyboard
• b) Writes text to the console window (Correct)
• c) Calculates the area of a circle
• d) Generates a random number

What are the two main types of data in C#?

• a) Text and numbers
• b) Integers and strings (Correct)
• c) Arrays and functions
• d) Boolean and objects

What is the difference between a = and a == operator?

• a) = assigns a value, == compares values (Correct)
• b) = adds two numbers, == subtracts two numbers
• c) Both are the same
• d) = is for strings, == is for numbers

What is the syntax for an if statement?

• a) if (condition) { code } (Correct)
• b) while (condition) { code }
• c) for (i = 0; i < 10; i++) { code }
• d) switch (variable) { case 1: code1; case 2: code2; }

What does the break keyword do inside a loop?

• a) Prints the loop counter
• b) Exits the loop immediately (Correct)
• c) Skips the current iteration of the loop
• d) Doubles the value of the loop counter

What are the basic building blocks of a program?

• a) Functions and variables (Correct)
• b) Classes and objects
• c) Loops and arrays
• d) Comments and documentation

What is the output of 5 + 3 * 2?

• a) 16
• b) 10 (Correct: PEMDAS, multiplication before addition)
• c) 5
• d) Error

Which data type can store decimal numbers?

• a) int
• b) double (Correct)
• c) string
• d) bool

What is a comment used for?

• a) To execute code (Not true)
• b) To explain and document parts of your code (Correct)
• c) To create variables
• d) To print messages to the console

What is the correct way to declare an integer variable named age?

• a) int age; (Correct)
• b) String age;
• c) Console.WriteLine(age);
• d) age = 20;

What does the modulo operator % do?

• a) Adds two numbers
• b) Subtracts two numbers
• c) Finds the remainder after division (Correct)
• d) Multiplies two numbers

What is the difference between an array and a string?

• a) An array holds multiple values, a string is a single character (Not true)
• b) An array stores numbers, a string stores text (Not always true)
• c) An array can have varying lengths, a string has a fixed length (Not true)
• d) An array holds any data type, a string only holds characters (Correct)

What is the keyword used to create a function?

• a) variable
• b) loop
• c) function (Not a C# keyword)
• d) void (Used in function declaration)

How do you call a function in C#?

• a) By writing its name inside main()
• b) By writing its name followed by parenthesis (Correct)
• c) By assigning it to a variable