Variables and Data types

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Programming in C#

Using variables

Memory is allocated to a variable at the time of its creation.

Syntax:

<datatype> <variableName>;

int empNumber;

empNumber = 100;

string empName = “M. Nolan”;

Data Types

Value Types

store actual values.

the values are stored in stack.

int, float, double, …

Reference Types

store the memory address

of other variables

in heap

string, class

Classification

Object

String

Class

Delegate

Interface

Array

Rules

Recommended CAMELCASE

int totMonths = 12

Question?

Question?

Comments and XML Documentation

Definition

Single-line Comments

Multi-line Comments

XML Comments

XML Documentation

Predefined XML Tags

Constants and Literals

Constants

possible to declare constants for all data types.

have to initialize a constant at the time of its declaration.

The compiler identify constants at the time of compilation

Using Literals

A literal is a static value assigned to variables and constants.

Numeric literals might suffix with a letter of the alphabet to indicate the data type of the literal.

Boolean => bool

Integer => int, uint (u), long (l), ulong (ul or lu)

long val = 53L;

Real => float(f), double(d), decimal(m)

float val = 1.66f;

Character

String => regular or verbatim.

Null

Keywords and Escape Sequences

Keywords

Escape Sequence Characters

Input and Output

Console Operations

are tasks performed on the command line interface.

All console application consist of three streams

Standard in

Standard out

Standard err

Output Methods

Console.Write()

Console.WriteLine()

Placeholders

Input Methods

Console.Read()

Console.ReadLine()

Convert Methods

Numeric Format Specifiers

Console.WriteLine(“{format specifier}, <variable name>”);

Numeric Format Specifiers

Standard Date and Time Format Specifiers

Standard Date and Time Format Specifiers

Question

What is result of following code snippet?