1. Thanachat Thanomkulabut
Method 1
Thanachat Thanomkulabut

2. Outline Method Type of Method No Returned value Returned value
Parameter Passing
No Parameter
Pass by value
Pass by reference
ref
out

3. Method Idea
Password
Input1
Input2
Light Switch
Safe
Calculator
Output

4. Pre-definded Method in C#
Console.WriteLine(” Hello world!”);
double j = Math.Sqrt(9);
Hello world! 9
Console.WriteLine
Math.Sqrt 3

5. Pre-definded Method in C#
int N = int.Parse(”5”);
double ans =Math.Max(9, 2);
String “5” 9 2
int.Parse
Math.Max
Int 5 9

6. a function/procedure owned by class.
What is Method?
Method is
a function/procedure owned by class.
System.Console.WriteLine(“Hello World!”);

7. Type of Method J = Math.Max(5, 20);
1. Non-Returned Value Method - Procedure
Console.WriteLine(“Hello World!”);
Method Name
Parameter
Class Name
2. Returned Value Method – Function
J = Math.Max(5, 20); 20
Class Name
Parameter
Method Name

8. Type of Method n1 n2 Hello world! Math.Max Console. WriteLine
Max of n1 & n2
Return no value (void)
Return Value

9. Method Example
* **
Program End
using System; class method_example { static void Main() { displaybox(); Console.WriteLine("Program End"); } static void displaybox() { Console.WriteLine("x"); Console.WriteLine("xx");
Monitor 1 3 2

10. Outline Method Overview Using Method Parameter Passing in Method
Pass by value
Pass by reference

11. Using User-Defined Method
1.Define Method
2.Call Method

12. Define Method in C# #remark return-type
static <return-type> <method-name>(<parameter list>) {
<const/variable declaration>;
<statements>; }
#remark return-type
return type can be int, double, string, …
and need return statement
void = return no value

13. Method Declaration Example
static void displaybox () { }
static int calage () { }
static int calbox(int x,int y) { }

14. Example1: Non-Returned Value
using System;
class NReturned {
static void Main() {
Console.WriteLine(”Hello, Mckazine”); }
HelloM
Hello, Mckazine

15. Example1: Non-Returned Value
using System;
class NReturned {
static void HelloM() {
Console.WriteLine(”Hello, Mckazine”); }
static void Main() {
HelloM();
Hello Mckazine

16. Example2: Non-Returned Value with parameters
using System;
class NReturned {
static void Main() {
Console.WriteLine(”Hi, AAA”);
Console.WriteLine(”Hi, BBB”);
Console.WriteLine(”Hi, CCC”); }
string
string name Hi
Hi, name

17. Example2: Non-Returned Value with parameters
using System;
class NReturned {
static void Hi(string name) {
Console.WriteLine(”Hi, {0}”, name); }
static void Main() {
Hi(”AAA”);
Hi(”BBB”);
Hi(”CCC”); Hi
string name
Hi, name
Monitor
Hi, AAA
Hi, BBB
Hi, CCC

18. **** * **** * **** * **** *
Example 3
static void Main(){ int i,j,n; Console.WriteLine("Square size = 2"); for(i=0;i<2;i++){ for(j=0;j<2;j++) Console.Write("*"); Console.WriteLine(); } Console.WriteLine("Square size = 4"); for(i=0;i<4;i++){ for(j=0;j<4;j++)
int n
DrawSquare
Result
...
**** * **** * **** * **** *
...
Square size = 2 ** **
Square size = 4 ****
****
...  
...

19. **** * **** * **** * **** *
Example 3
static void Main(){
Console.WriteLine("Square size = 2");
drawSquare(2);
Console.WriteLine("Square size = 4");
drawSquare(4); }
static void drawSquare(int n){
int i,j;
for(i=0;i<n;i++){
for(j=0;j<n;j++)
Console.Write("*");
Console.WriteLine();
Monitor
DrawSquare
int n
**** * **** * **** * **** *
... 
Square size = 2
** **
Square size = 4
**** **** ****
****

20. Self Test 1 Write the method PrintNumber(n) Example PrintNumber
Recieve parameter n
Show n
Example
int n 7
PrintNumber
PrintNumber n

21. Self Test 1 static void PrintNumber(int n) { int i;
Write the method PrintNumber(n)
Recieve parameter n
Show n n
static void PrintNumber(int n) {
int i;
for(i=1;i<=n;i++)
Console.Write(i); }

22. Outline Method Type of Method No Returned value Returned value
Parameter Passing
No Parameter
Pass by value
Pass by reference
ref
out

23. Define Method in C# #remark return-type
static <return-type> <method-name>(<parameter list>) {
<const/variable declaration>;
<statements>; }
#remark return-type
return type can be int, double, string, …
and need return statement
void = return no value

24. Return value method n n n ans = Math.Sqrt(n); Math.Sqrt
static void PrintNumber(int n) {
double n, ans;
n = int.Parse(Console.ReadLine());
ans = Math.Sqrt(n);
Console.Write(“Root {0} is equal {1}",n,ans); }
Math.Sqrt n n

25. Example 1: Returned Value
using System;
class Returned {
static void Main() {
int j;
j = 2*2;
Console.WriteLine(”{0}”, j);
j = 5*5; } n
Power2 n2

26. Example 1: Returned Value
using System;
class Returned {
static int Power2(int n) {
return n*n; }
static void Main() {
int j;
j = Power2(2); //j=2*2;
Console.WriteLine(”{0}”, j);
j = Power2(5); //j=5*5;
Power2 n n2
Result 4 25

27. Example 2: Returned Value
static void Main() {
int n,i,count=0;
n = int.Parse(Console.ReadLine());
for(i=1;i<=n;i++)
if(n%i==0) count++;
if(count==2)
Console.Write("{0} is Prime.",n); }
Process for check Prime number.

28. Example 2: Returned Value
static void Main() {
int n,i,count=0;
n = int.Parse(Console.ReadLine());
for(i=1;i<=n;i++)
if(n%i==0) count++;
if(count==2)
Console.Write("{0} is Prime.",n); } x
Is_Prime
True if x is prime. False if x is not prime

29. Example 2: Returned Value
static bool Is_Prime(int x){
int i,count=0;
for(i=1;i<=x;i++)
if(x%i==0) count++;
if(count==2)
return true;
else
return false; }
static void Main(){
int n = int.Parse(Console.ReadLine());
if(Is_Prime(n) == true)
Console.Write("{0} is Prime.",n);
Is_Prime x
True if n is prime. False if n is not prime

30. Example 3: Returned Value
static void Main() {
double r,h,V;
r = double.Parse(Console.ReadLine());
h = double.Parse(Console.ReadLine());
V = Math.Pi*r*r*h;
Console.Write("V = {0}",V); } r h
V_Cylinder V

31. Example 3: Returned Value
V_Cylinder r V h
static double V_Cylinder(double r, double h){
return Math.PI*r*r*h; }
static void Main() {
double r,h,V;
r = double.Parse(Console.ReadLine());
h = double.Parse(Console.ReadLine());
V = V_Cylinder(r,h);
Console.Write("V = {0}",V);

32. Self Test 1 Define Power4(n) Method Ex. int j = Power4(3); //Return 81
Return n*n*n*n
Ex. int j = Power4(3); //Return 81
int
int n
static ____ Power4(___________________) { }
int ans;
return n*n*n*n;
ans = n*n*n*n;
reture ans;

33. Self Test 2 Define Max(x, y, z) Method
Return Max Value
Ex. int j = Max(5, 20, 12); //Return 20
int
int x, int y, int z
static ____ MAX(___________________) { }
int ans;
if(x >= y && x >= z)
return x;
ans = x;
else if(y >= x && y >= z)
ans = y;
return y;
else
return z;
ans = z;
return ans;

34. C# Structure – Multiple Methods
Namespace
Class
Main()
Method1()
Method2()
Method3()
MethodN()

35. Example 5 : Mutiple Method
static double FindMedian(double n1, double n2) {
return (n1+n2)/2; }
static void Report(double x, double y)
Console.Write("Median = {0} ", FindMedian(x,y));
static void Main(string[] args) {
Console.Write("Please Key 2 Input : ");
double a1 = double.Parse(Console.ReadLine());
double a2 = double.Parse(Console.ReadLine());
Report(a1, a2); }

36. Any question?