itf11006.net the basics. data types – value types – reference types flow control – conditional...
TRANSCRIPT
ITF11006 .NET
The Basics
The Basics• Data Types
– Value Types– Reference Types
• Flow Control– Conditional– Loop
• Miscellaneous– Enumerations– Namespaces
• Class / Struct– Data Members– Functional Mem
• Base Classes– System.Object– System.String
Variables/Constants
• Syntax[modifier] type identifier [= expression];
• Scope
– Class/Block
• Constants[modifier] const type identifier [= constant-expression];
• Type Inferencevar identifier [= expression];
Predefined Data Types
• Value Types
• Reference Types
Predefined Data Types
• Value Types
– Integer Types
– Floating Point Types
– Decimal Type
– Boolean Type
– Character Type
Integer Types
C# data type Description Class name Range
sbyte A 8-bit signed integer. System.SByte -128:127
short A 16-bit signed integer. System.Int16 -32.768: 32.767
int A 32-bit signed integer. System.Int32 -2.147.483.648: 2.147.483.647
long A 64-bit signed integer. System.Int64 -9.223.372.036.854.775.808: 9.223.372.036.854.775.807
byte An 8-bit unsigned integer. System.Byte 0:255
ushort A 16-bit unsigned integer. System.UInt16 0:65535
uint A 32-bit unsigned integer. System.UInt32 0:4.294.967.295
ulong A 64-bit unsigned integer. System.UInt64 0:18.446.744.073.709.551.615
Floating Point
C# data type Description Class name Significant fig. Range
float A single-precision (32-bit) floating-point number.
System.Single 7 +1.5x10-45 to +3.4x1038
double A double-precision (64-bit) floating-point number.
System.Double 15/16 +5.0x10-324 to +1.7x10308
Decimal Type
C# data type Description Class name Significant fig. Range
decimal A 96-bit decimal value.(128 bit space!)
System.Decimal 28 +1.0x10-28 to +7.9x1028
Boolean Type
C# data type Description Class name Range
bool Logical true or false System.Boolean true or false
Character TypeC# data type Description Class name
char 16 bits. Represents a single (Unicode) character System.Char
Nullable Types (http://msdn.microsoft.com/en-us/library/1t3y8s4s(v=VS.100).aspx)
• T? orSystem.Nullable(Of T)
• Ordinary type plus null
Predefined Reference Types
• Object• String
Flow Control• Conditional
– if– switch
• Loop– for– while– do..while– foreach
• Jump– goto– break– continue– return
Conditional Statements
• if if (expression) statement1 [else statement2]
• switch switch (expression){
case constant-expression:
statement
jump-statement
[default:
statement
jump-statement]
}
Loops
• for for ([initializers]; [expression]; [iterators]) statement
• while while (expression) statement
• do..while do statement while (expression);
• foreach foreach (type identifier in expression) statement
Jump Statements
• goto• break• continue• return• (throw)
Enumerations
• enum[modifiers] enum identifier [:base-type]
{enumerator-list} • Inherits from System.Enum• Flags Attribute• Use enumerations
Namespaces
• Logical grouping of functionality• <company>.<technology/sw package>• Using directive
Class (/Struct)
• Data Members– Fields– Constants– Events
• Function Members– Methods– Properties– Constructor– Destructor– Operators– Indexers
Methods
• syntax[modifiers] return-type method-name([formal-parameter-list]) { statement(s)}
• Named Argumentsstring FullName(string firstName, string lastName)…
FullName(“Ole”, “Olsen”);FullName(lastName: “Olsen”, firstName: “Ole”);
• Optional Arguments
• Method Overloading
Properties
• syntax[modifiers] type identifier {
set {accessor-body} get {accessor-body}
}
• Auto-Implementedpublic string Age(get; private set;)
• Choosing Between Properties and Methodshttp://msdn.microsoft.com/en-us/library/ms229054.aspx
Construction and Disposal
• Constructors– Instance– Class– Calling
• Destructor– Why– How (pattern)
• Dispose vs. Close
Operators
• Operator Overloading
public static Vector operator * (double lhs, Vector rhs)
{
return new Vector(lhs * rhs.x, lhs * rhs.y, lhs * rhs.z);
}
public static Vector operator * (Vector lhs, double rhs)
{
return rhs * lhs;
}
Console.WriteLine("vect2 * 2 = " + ( vect2 * 2).ToString());
Indexerspublic char this[int index]
{
get
{
...
}
set
{
...
}
}
Instance vs. Class Level
• Static• this vs. class name
Struct
• No inheritance (almost)• Constructors• Fields are sometimes declared public!• Structs are value types
Struct vs. class
• Footprint• Performance
object (System.Object)
• Methods
• Comparing for Equality– Reference Types– Value Types
Method Access
string ToString() public virtual
int GetHashCode() public virtual
bool Equals(object obj) public virtual
bool Equals(object objA, object objB) public static
bool ReferenceEquals(object objA, object objB) public static
Type GetType() public
object MemberwiseClone() protected
void Finalize() protected virtual