Programming Concepts: Console Applications & Loops

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Questions and Answers

What keyword is used to declare output parameters in a method?

out (correct)
params
in
ref

Which of the following statements about output parameters is true?

They create a new storage location.
The actual argument in the method invocation must also be declared as out. (correct)
They require the variable to be initialized before being passed.
They cannot be used in methods returning a value.

What is the purpose of the params keyword when defining a method?

To allow passing of variable number of arguments. (correct)
To declare an array of return types.
To allow passing of fixed number of arguments.
To specify return values.

In the provided example, what will the output be from Console.WriteLine("m = " + m); after calling Square(10, out m);?

100 (C) Signup and view all the answers

Which of the following methods of passing parameters allows modifications to the original variable in the calling code?

Reference parameters with the ref keyword. (A), Output parameters with the out keyword. (D) Signup and view all the answers

What type of user interface do Console Applications primarily utilize?

Command Line User Interface (CUI) (C) Signup and view all the answers

Which of the following is a characteristic of Console Applications?

They do not support mouse pointers. (D) Signup and view all the answers

What best describes the type of loop represented by the while statement?

A pre-test loop (C) Signup and view all the answers

In a while loop, what happens if the test condition evaluates to false?

The loop body is not executed. (D) Signup and view all the answers

What is the address of the while loop syntax?

while(test condition) { Body of the Loop; } (A) Signup and view all the answers

What is the purpose of parameters in C# methods?

To pass values and receive results. (C) Signup and view all the answers

What is a key difference between Console Applications and applications written in C or C++?

Console Applications offer no visual components. (B) Signup and view all the answers

Which statement is true regarding the execution of a while loop?

The loop's body may not run if the condition is false from the beginning. (D) Signup and view all the answers

What happens to the actual parameter when a method parameter is passed by value?

A new variable is created in the method. (A) Signup and view all the answers

What keyword must be used to pass a parameter by reference in C#?

ref (C) Signup and view all the answers

In which scenario would you typically use pass by reference?

When you need to update the original variables. (B) Signup and view all the answers

Which statement about passing parameters by value is true?

The method can work with a new copy of the actual parameter. (C) Signup and view all the answers

What is the effect of declaring a parameter as 'ref' in a method?

It allows changes to the original argument. (B) Signup and view all the answers

Which of the following describes parameter arrays?

They allow methods to accept a variable number of arguments. (C) Signup and view all the answers

If two parameters are passed by reference and swapped, what is affected?

Both parameters' values are changed simultaneously. (C) Signup and view all the answers

When passing by value, how many copies of a variable exist within the method?

Two copies. (C) Signup and view all the answers

What is the primary purpose of a one-dimensional array?

To store a single list of items with a unique identifier (A) Signup and view all the answers

Which syntax correctly declares an integer array named 'myArray' that can hold 5 elements?

int[] myArray = new int[5]; (D) Signup and view all the answers

What is the correct way to initialize the first element of an integer array named 'marks' to 60?

marks[0] = 60; (A) Signup and view all the answers

Which of the following is NOT a characteristic of a two-dimensional array?

It stores elements in a linear fashion. (C) Signup and view all the answers

In which line is the creation of a two-dimensional array performed correctly?

int[,] myArray = new int[3, 4]; (D) Signup and view all the answers

What does method overloading allow in programming?

Multiple methods with the same name and different parameter lists (A) Signup and view all the answers

What is required to access a specific value in an array?

Using an index number or subscript (C) Signup and view all the answers

What will be the output of calling `add(312L, 22L, 21)` if the method is defined for adding long integers and an integer?

355 (A) Signup and view all the answers

What can be said about the `Parray()` method in the provided code snippet?

It is an overloaded method (A) Signup and view all the answers

Which of the following statements correctly describes arrays?

Arrays must have a fixed size after declaration. (A) Signup and view all the answers

What will be the result of calling `Console.WriteLine(add(2.6F, 3.1F));`?

5.7 (C) Signup and view all the answers

In which scenario is method overloading particularly useful?

When the same functionality is needed with different types of inputs (A) Signup and view all the answers

What allows methods to have the same name while differing in parameters and definitions?

Method Overloading (A) Signup and view all the answers

What does an index number or subscript in an array signify?

The position of a value in the array (B) Signup and view all the answers

In the example of method overloading, what will be the output of calling add(2,3)?

6 (A) Signup and view all the answers

Which data type is returned by the add method that takes two float parameters?

float (C) Signup and view all the answers

What happens when the Parray() method is called with an array as an argument?

It directly modifies the array elements. (B) Signup and view all the answers

Which statement describes the primary function of arrays in programming?

To store a collection of elements of the same type (A) Signup and view all the answers

Which practice is essential for method overloading to be effective?

Using different parameter types or counts (C) Signup and view all the answers

What is the output of calling add(312L, 22L, 21) if it is defined for long integers and an integer?

355 (B) Signup and view all the answers

Study Notes

Console Applications

Console Applications feature a user interface similar to MS-DOS, UNIX, etc.
Known as CUI (Character User Interface) applications, they operate entirely within the CUI environment.
Comparable to C or C++ applications, lacking graphical user interface elements.
Do not support GUI elements like mouse pointers, colors, buttons, or menu bars.

Decision Making & Looping

While Statement

Looping is the repeated execution of a block of statements.
While statements are entry-controlled loops; the condition is checked before execution.

Syntax:

initialization;
while(test condition) {
    Body of the Loop…
}

Method Parameters in C#

Four types of parameters: Value Parameters, Reference Parameters, Output Parameters, Parameter Arrays.

Pass By Value

Default behavior in method parameters where values are copied.
Changes to formal parameters do not affect actual parameters.
Example demonstrates the use of an integer variable passed by value.

Pass By Reference

Achieved by using the 'ref' keyword, linking actual and formal parameter storage.
Allows for modifications of the original variable values within the calling method.
Example illustrates swapping values using reference parameters.

Output Parameters

Use the 'out' keyword to return results to the calling method without creating a new storage location.
Required declaration for both formal and actual arguments in the method.

Variable Argument Lists

Enables methods to accept variable numbers of arguments through parameter arrays.
Parameter arrays are declared using the 'params' keyword and must be one-dimensional.

Method Overloading

Allows multiple methods with the same name but different parameter lists.
Useful for performing similar tasks that require different inputs.
Examples include methods for adding integers, floats, and long integers.

Arrays

Introduction

An array is a collection of contiguous data items sharing a common name.
Values are accessed using an index or subscript.
The collection of values is termed an array, while individual items are called elements.

One-Dimensional Arrays

Consist of a list of items indexed by a single variable name.
Declaration syntax: type[] arrayname;
Initialization and creation methods outlined with examples for integers and floats.
Length of the array can be obtained using the Length property.

Two-Dimensional Arrays

Designed to store a table of values, defined by rows and columns.
Indexed with two indices; first for rows, second for columns.
Declaration and creation syntax provided, including initialization examples with arrays of multiple elements.

Programs

Exercise included to write a program sorting an array of 5 numbers from user input.
Example for multiplication table implementation using a two-dimensional array structure.

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Description

This quiz focuses on the fundamentals of console applications within programming environments like MS-DOS and UNIX. It covers important concepts such as decision making and looping structures, specifically the while statement. Test your understanding of these essential programming principles from Chapter 1.