methods
DESCRIPTION
Methods, Passing value types by value and by reference, Passing reference types by value and by reference, Passing variable number of arguments, Named arguments, Optional parameters.TRANSCRIPT
MethodsBhushan Mulmule
bhushan.mulmule@dotnetvideotutorial.comwww.dotnetvideotutorial.com
For video visit www.dotnetvideotutorial.com
Methods
Passing value types
By Value
By Reference
Passing reference types
By Value
By Reference
Agenda
Features
Variable arguments
Named arguments
Optional parameters
MethodsA method is a code block containing a series of statements.
Methods are declared within a class or struct by
specifying
Access Modifier
Other Modifiers
Return value
Name of the method
Method parameters.
public static int add(int no1, int no2) { }
www.dotnetvideotutorial.com
Possible Combinations• Method without parameter and
no return valuevoid fun1()
• Method with parameter and no return value
void fun2(string name)
• Method with parameter and return value
int fun3(int no1, int no2)
• Method without parameter but with return value
string fun4()
Method without parameter and No return value
static void Main(string[] args) { greet();
Console.ReadKey(); }
static void greet() { Console.WriteLine("Hello"); }
www.dotnetvideotutorial.com
static void Main(string[] args){ greet("Mr. Anderson");
Console.ReadKey();}
static void greet(string name){ Console.WriteLine("Hello " + name);}
Method with Parameters but No Return value
Mr. Anderson
name
www.dotnetvideotutorial.com
Method With Parameters and Return value static void Main(string[] args) { int no1 = 10, no2 = 20; int result = add(no1, no2);
Console.WriteLine("Result = {0}", result);
Console.ReadKey(); } static int add(int no1, int no2) { int result = no1 + no2; return result; }
no110
no220
no110
no220
result30
result30
www.dotnetvideotutorial.com
Compact Format
static void Main(string[] args){ Console.WriteLine(add(25,50));}
static int add(int no1, int no2){ return no1 + no2;}
no125
no250
www.dotnetvideotutorial.com
Fn without Parameter but with return value
static void Main(string[] args) { Console.WriteLine(GetTime());
Console.ReadKey(); }
static string GetTime() { string time = DateTime.Now.ToShortTimeString(); return time; }
www.dotnetvideotutorial.com
ref and out keyword used to pass arguments by
reference
ref: to pass references of initialized variables
out: to pass references of uninitialized variables
value type as well as reference type can be
passed by reference
Passing References
www.dotnetvideotutorial.com
static void Main(string[] args){
int no1 = 25, no2 = 50;Console.WriteLine("Before swaping: no1 = {0}, no2 = {1}", no1,
no2);Swap(ref no1, ref no2);Console.WriteLine("After swaping: no1 = {0}, no2 = {1}", no1,
no2);
Console.ReadKey();}static void Swap(ref int no1,ref int no2){
int temp = no1;no1 = no2;no2 = temp;
}
ref keyword
25
no1
542050
no2
5424
5420
no1542
4
no2
25temp
50 25
www.dotnetvideotutorial.com
out keywordstatic void Main(string[] args)
{ float radius, area, circumference; Console.WriteLine("Enter Radius of Circle: "); radius = Convert.ToInt32(Console.ReadLine()); Calculate(radius, out area, out circumference); Console.WriteLine("Area = " + area); Console.WriteLine("Circumference = " + circumference);
}
static void Calculate(float radius, out float area, out float circumference) { const float pi = 3.14f; area = 2 * pi * radius; circumference = pi * radius * radius; }
radius
5420
5
area
5424
circum
5428
78.5
radius5
area542
4
circum542
8
31.4
www.dotnetvideotutorial.com
Passing Reference TypesReference type can be passed by value as well by
reference
If passed by value - content of object reference is
passed
If passed by reference - reference of object
reference is passed502
82000 5028
obj
www.dotnetvideotutorial.com
Passing string by valuestatic void Main(string[] args){ string str = "Milkyway"; Console.WriteLine("str = " + str); ChangeString(str); Console.WriteLine("\nstr = " + str);}
static void ChangeString(string str){ Console.WriteLine("\nstr = " + str); str = "Andromeda"; Console.WriteLine("\nstr = " + str);}
5028
Milkyway
Andromeda
5028
5028
6252
6252
str
str
www.dotnetvideotutorial.com
Passing string by referencestatic void Main(string[] args){ string str = "Milkyway"; Console.WriteLine("str = " + str); ChangeString(ref str); Console.WriteLine("\nstr = " + str);
Console.ReadKey();}
static void ChangeString(ref string str){ Console.WriteLine("\nstr = " + str); str = "Andromeda"; Console.WriteLine("\nstr = " + str);}
5028
Milkyway
Andromeda
5028
6252
6252
2020
2020
str
str
www.dotnetvideotutorial.com
Passing Array by valuestatic void Main(string[] args){ int[] marks = new int[] { 10, 20, 30 };
Console.WriteLine(marks[0]); ChangeMarks(marks); Console.WriteLine(marks[0]);}
static void ChangeMarks(int[] marks){ Console.WriteLine(marks[0]); marks[0] = 70; Console.WriteLine(marks[0]);}
5028
5028
10 20 30
5028
marks
marks
70
www.dotnetvideotutorial.com
Flexibility
Variable Arguments
Named Argum
ents
Optional
Parameters
Passing variable number of argumentsstatic void Main(string[] args){ Console.Write("Humans : "); printNames("Neo", "Trinity", "Morphious", "Seroph"); Console.Write("Programs : "); printNames("Smith", "Oracle");}static void printNames(params string[] names){ foreach (string n in names) { Console.Write(n + " "); } Console.WriteLine();}
www.dotnetvideotutorial.com
Named Arguments
static void Main(string[] args){
int area1 = CalculateArea(width:10,height:15);Console.WriteLine(area1);
int area2 = CalculateArea(height: 8, width: 4);Console.WriteLine(area2);
}static int CalculateArea(int width, int height){ return width * height;}
www.dotnetvideotutorial.com
Optional Parameters
static void Main(string[] args){ Score(30, 70, 60, 80); Score(30, 70, 60); Score(30, 70);}
static void Score(int m1,int m2,int m3 = 50,int m4 = 30){ Console.WriteLine(m1 + m2 + m3 + m4);}
www.dotnetvideotutorial.com
