Java Programming - Chapter 8 (in Thai)

7/25/2019 Java Programming - Chapter 8 (in Thai)

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Computer Programming using JavaMethods - 08

1 1 1 (main)

CHAPTER

8

cl ass Oper at i on {

} / / End of cl ass

cl ass Oper at i on {

} / / End of cl ass

(Methods)

1. (Introduction to Methods)

1.

1) (Methods) Subroutine, Sub-program

Function 2) (Class) 3)

1 1 1 (1)

1 1 mai n-

(2)

1 mai n(mai nmai n)

4)

1

main( . . . ) {

/ / add

/ / sub

}

main( . . . ) {add( )sub(). . .

}

add( . . . ) {

}

sub( . . . ) {

}

2

5

4

7

3

1

6

123456

789

1

2

publ i c cl ass Exampl e {publ i c st at i c voi d mai n( St r i ng[ ] ar gs) {int n = add(4, 10);Syst em. out . pr i nt l n( n) ;

}publ i c st at i c int add(int x, int y) {

return x + y;}

}

1 add( 4, 10) 2 410

3 add( i nt x, i nt y)

4 4 +10

5 r et ur n 14

7 Syst em. out . pr i nt l n( n) 6 i nt n =14


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Computer Programming using Java 08 - Methods

1 [] ()() (20 )

1)

Test 3 2) mai n(Compile) (Run) 3)

mai nmodmul 4)

modmul

5)

modmai n

6)

modmod7) mul 2 mul 8) mod1 mod9) n7 n12 10) x15 x16 11)

xmod4 mod( 4)

12)

mul i nt 13)

modi nt 14)

7 8 10.0 1.0 15)

mul ( 2, 1) 2.016)

mod( 8, 3) 2.017)

Test 11.018)

return13 16 19)

mul 12-13 r et ur n x * y; 20) mai nreturnmai nvoi d

12

3456789101112131415

161718

i mpor t j ava. ut i l . Scanner ;publ i c cl ass Test {

publ i c stati c voi d mai n( St r i ng[ ] ar gs) {Scanner kb = new Scanner ( Syst em. i n) ;doubl e a = kb. next Doubl e( ) ;i nt b = kb. next I nt ( ) ;doubl e n = mul ( a, b) ;i nt m = mod( 13) ;System. out . pr i nt l n( n + m) ;

}pr i vat e st at i c doubl e mul ( doubl e x, i nt y) {

doubl e n = x * y;r et ur n n;

}pr ot ect ed st at i c i nt mod( i nt x) {

r et ur n x % 3;}}

5.0

2

publ i cst at i cpr i vat e stat i c

12


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2.(Method Structure and Creating Method)

1.

2

6

2. (Head)1) (Modifier)

publ i c, pri vat e, pr ot ect ed, stat i cpublic static

2)

(Method Type) (Return Type)byte, shor t , i nt , l ong, f l oat ,doubl e voi d

(Brackets)

publ i c st at i c double add( int x, int y) {

double cal = x + y;return cal;

}

pr ot ect ed void show( f l oat y, St r i ng s)

( ) {. . .

} .

1 2 3 4

5

6

-

1-4 (Head)

5-6 (Body)

pr i vat e stat i c int[] sor t ( i nt x[ ] ) int[][]

public static doubl e power ( doubl e n)

1


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3) (Method Name) () get I D( ) ,addNumber ( ) -

4)

(Parameters) (Comma) set ( i nt a, i nt b) set ( i nt a, b)

2 [] (10 )1) square 1

(2 )doubl e square( )

2) root 1 (2 )

pr ot ected st at i c ( )

3)

showName 1

(2 )pr i vat e st at i c showName( )

4)

countX 1 (2 )

stat i c

5)

revArray 1 1 (Reverse) (2 )

revArray

publ i c st at i c doubl e add(i nt x, i nt y)

publ i c doubl e mul ( int x,double y,int z)

publ i c st at i c i nt f i nd( int x, int y[][])


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3. (Body)1) i f - el se,

whi l e, f or , Scanner 1-7 2)

(Return Value) (Method Type) (Return Type) returnreturnvoi dreturn

3) 1 ()

3 [] () () (10 )

1)

publ i c st at i c pr i nt Er r or ( St r i ng msg) {Syst em. er r . pr i nt l n( msg) ;}

2)

pr ot ected stat i c i nt f l i p( i nt n) {i f ( n == 1) n = 0;

}

3) publ i c st at i c f l oat max( l ong x, y) {

i f ( x > y) r et ur n x;el se r et ur n y;

}

4) pr i vat e st at i c voi d showChar ( ) {f or ( char i = ' 0' ; i


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5) st at i c St r i ng cal Gr ade( i nt x) {

i f ( x > 80) r et ur n "A";el se i f ( x < 50) r et ur n "F";el se Syst em. out . pr i nt l n( "C") ;

}

6)

doubl e getLen( doubl e dx, doubl e dy) {doubl e dx = Math. abs( dx) ; r etur n Math. sqrt ( dx*dx + dy*dy) ;

}

7) publ i c pr i vat e bool ean checkLen( i nt x[ ] , i nt y[ ] ) {r et ur n x. l engt h == y. l engt h;

}

8) publ i c f l oat get Locat i onPoi nt ( ) {r et ur n 0. 0;

}

9)

publ i c stat i c i nt f ac( i nt x) {i f ( x


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4) fullName () (4 )

5 [] fac() (Factorial) fac(3) = 6, fac(5) = 120(10 )

6 [] findMax 50 50 (10 )

7 [] underX() a x ax (10 )


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8 [] isPrime() (10 )

9 [] memberOfArray() -a x 1 -1 (10 )


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10 [] appendArray() a[] = {1, 2, 3 }b[] = {5, 6}appendArray(a, b) = {1, 2, 3, 5, 6}(10 )

3. (Simple Method Calling)

1.

2 1)

2)

2.

1) add( ) (-)2) add(5, 3) (

add( x, y * 2) )3) i nt n = add( 5, 3) ;

(1)byte, shor t , i nt , l ong, f l oat , doubl eSt r i ng s = getName( 53300121) ;

(2)

void() showName( 53300121) ;

123456

publ i c st at i c voi dmain( St r i ng[ ] ar gs) {i nt n = add(5, 3);

}publ i c st at i c i nt add( i nt x, i nt y) {

r etur n x + y;}

mai n(add)

add (mai n)


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4) (1)

i nt n[] = { 1, 2, 3, 4 };i nt c = under X( n, 3) ;

(2)

(new) i nt x[ ] = { 1, 2, 3, 4 }, y[ ] = { 5, 7, 9 };i nt z[] = appendAr r ay( x, y) ;

3.

1) ( )

(byte, shor t ) i nt n = add(x, y); 2) ()

publ i c . . . add(int x, int y)

11 [] (10 )

1. publ i c stati c voi d set ( i nt m, i nt n)

2. publ i c stat i c i nt cal s( i nt m, f l oat n)

3. publ i c stat i c St r i ng t oSt r i ng( i nt [ ] n)

12345

67891011

publ i c st at i c voi d mai n( St r i ng[ ] ar gs) {String s = getName(53300121);System. out . pr i nt l n( s);showName(53300121);

}

publ i c stat i c St r i ng getName( i nt i d) {r etur n "Wongyos" ;}publ i c st at i c voi d showName( i nt i d) {

Syst em. out . pr i nt l n( "Wongyos" ) ;}

mai nget Namei nt

s

mai nshowNamei nt

1234567

publ i c st at i c voi d mai n( St r i ng[ ] ar gs) {i nt x = 5, y = 3;i nt n = add(x, y);

}publ i c st at i c i nt add(int x, int y) {

r etur n x + y;}

-

xymai nxyadd


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4. publ i c st at i c i nt [ ] get ( i nt m, St r i ng s)

5. publ i c stat i c voi d sor t ( doubl e d[ ] )

6. publ i c stat i c bool ean check( l ong i d)

7. publ i c stati c i nt f l i p( i nt m, bool ean b)

8. publ i c st at i c doubl e[ ] i nput Ar r ay( )

9. publ i c stat i c voi d showLogo( )

10. publ i c st at i c byt e f ( i nt m, i nt n, i nt p)

12 [ ] ArrayUtility (75 )import java.util.Scanner;

public class ArrayUtility {

//[] main()(5 )public static void main(String[] args) {

int a[] = { 5, 1, 6, 1, 4, 1, 2, 1, 4, 3, 1, 5, 7, 2, 1, 1 };

sort(a);System.out.println(max(a));

System.out.println(min(a));

1. count ( )

2. mode( )

3. maj or i t y( )

4. medi an( )

5. r ange( )

} //End of main


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//[] swap()ijswap(a, i, j) ija (5 )

//[] sort()(Bubble Sort) (10 )

//[] count() k-() (10 )


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//[] mode() (10 )

//[] majority() -1 (10 )

//[] median() (10 )


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//[] max() (5 )

//[] min() (5 )

//[] range() (5 )

} //End of class

13 [ ] main() 1 2 (5-6 ) (40 )


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1234

567891011121314151617181920212223242526272829303132333435363738394041424344

454647

i mpor t j ava. i o. *;i mpor t j ava. ut i l . Scanner ;i mpor t j l ab. gr aphi cs. DWi ndow;publ i c cl ass OneMai nOneMethod {

publ i c stati c voi d mai n( St r i ng[ ] ar gs) {Scanner kb = new Scanner ( Syst em. i n) ;

System. out . pr i nt ( "Ent er a[ ] si ze: ") ;i nt x = kb. next I nt ( ) ;i nt a[ ] = new i nt [ x] ;f or ( i nt i = 0; i < a. l engt h; i ++) {

System. out . pr i nt ( "Ent er member : ") ;a[ i ] = kb. next I nt ( ) ;

}

System. out . pr i nt ( "Ent er b[ ] si ze: ") ;i nt y = kb. next I nt ( ) ;i nt b[ ] = new i nt [ y] ;f or ( i nt i = 0; i < b. l engt h; i ++) {

System. out . pr i nt ( "Ent er member : ") ;b[ i ] = kb. next I nt ( ) ;

}

Syst em. out . pr i nt ( "Check ar r ay equal s bef or e sor t : ") ;i f ( a. l engt h == b. l engt h) {

i nt count = 0;f or ( i nt i = 0; i < a. l engt h; i ++) {

i f ( a[ i ] == b[ i ] ) count ++;}i f ( count == a. l engt h) {

Syst em. out . pr i nt l n( "equal s") ;} el se {

Syst em. out . pr i nt l n( "not equal s") ;}

} el se {Syst em. out . pr i nt l n( "not equal s") ;

}

f or ( i nt i = a. l engt h - 1; i >= 1; i - - ) {f or ( i nt j = 0; j < i ; j ++) {

i f ( a[ j ] > a[ j + 1] ) {i nt t = a[ j ] ;a[ j ] = a[ j + 1] ;a[ j + 1] = t ;

}}

}

Ent er a[ ] si ze: 3Ent er member : 1Ent er member : 2Ent er member : 3Ent er b[ ] si ze: 3Ent er member : 2

Ent er member : 1Ent er member : 3Check ar r ay equal s bef ore sor t : not equal sCheck ar r ay equal s af t er sor t : equal sa[ ] : 1 2 3b[ ] : 1 2 3


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(5-6 main()) import java.util.Scanner;

public class OneMainManyMethods {

484950515253

54555657585960616263646566

67686970717273747576777879

808182838485

f or ( i nt i = b. l engt h - 1; i >= 1; i - - ) {f or ( i nt j = 0; j < i ; j ++) {

i f ( b[ j ] > b[ j + 1] ) {i nt t = b[ j ] ;b[ j ] = b[ j + 1] ;b[ j + 1] = t ;

}}

}

Syst em. out . pr i nt ( "Check ar r ay equal s af t er sort : ") ;i f ( a. l engt h == b. l engt h) {

i nt count = 0;f or ( i nt i = 0; i < a. l engt h; i ++) {

i f ( a[ i ] == b[ i ] ) count ++;}i f ( count == a. l engt h) {

Syst em. out . pr i nt l n( "equal s") ;} el se {

Syst em. out . pr i nt l n( "not equal s") ;}

} el se {Syst em. out . pr i nt l n( "not equal s") ;

}

System. out . pr i nt ( "a[ ] : ") ;f or ( i nt i = 0; i < a. l engt h; i ++) {

System. out . pr i nt ( a[ i ] + " ") ;}System. out . pr i nt l n( ) ;

System. out . pr i nt ( "b[ ] : ") ;

f or ( i nt i = 0; i < b. l engt h; i ++) {System. out . pr i nt ( b[ i ] + " ") ;}System. out . pr i nt l n( ) ;

} / / End of mai n} / / End of cl ass


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} //End of class


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4. (Overloading Methods)

1. (Overloading Methods)2 1)

2)

2.

1) (Return Type) (

)2)

()

3)

(Compile-time Error)

14 [] (Overloading Method) (15 )

1publ i c st at i c doubl e m( i nt n) {

r et ur n n * n;}

2publ i c st at i c i nt m( doubl e n) {

return ( i nt ) ( n * n) ;}

3publ i c stati c bool ean m( i nt n, i nt x) {

r eturn n == x;}

4publ i c stat i c doubl e m( i nt a, i nt b, i nt c) {

r et ur n ( doubl e) ( a * b * c) ;}

5publ i c stati c i nt m( char c) {

return ( i nt ) c;}

6publ i c st at i c St r i ng m( doubl e n, i nt x) {

r eturn n + " " + x;}

7publ i c st at i c i nt m( doubl e x, doubl e n) {

return ( i nt ) ( n * x) ;}

publ i c stat i c i nt t est( int x) publ i c stat i c i nt t est( int x, int y)

publ i c stat i c i nt t est( int x) publ i c stat i c i nt t est( double x)

test 1 test 2

t est i nt t est doubl e


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1. Syst em. out . pr i nt l n( m( 10) ) ;

2. Syst em. out . pr i nt l n( m( 1, 2. 5) ) ;

3. Syst em. out . pr i nt l n( m( 11. 0) ) ;

4. Syst em. out . pr i nt l n( m( 6. 0f ) ) ;

5. Syst em. out . pr i nt l n( m( 12, 2)) ;

6. System. out . pr i nt l n( m( ' 1' ) ) ;

7. Syst em. out . pr i nt l n( m( 10. 0, 2) ) ;

8. Syst em. out . pr i nt l n( m( 2, 2, 1) ) ;

9. Syst em. out . pr i nt l n( m( m( 5, 1, 2) ) ) ;

10. Syst em. out . pr i nt l n( m( m( 5, 1. 0f ) ) ) ;

11. Syst em. out . pr i nt l n( m( 1. 0f , 2) ) ;

12. Syst em. out . pr i nt l n( m( 0L, 1, 1) ) ;

13. Syst em. out . pr i nt l n( m( 0. 0f , ( byt e) 1) ) ;

14. Syst em. out . pr i nt l n( m( ( byt e) 1. 3, 1) ) ;

15. Syst em. out . pr i nt l n( m( 1. 1) ) ;

15 [ ] (Overloading Method) - (15 )import java.util.Scanner;

public class Overload {

//main() showName() -(3 )

public static void main(String[] args) {

} //End of main


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112 Computer Programming using Java 08 - Methods

//showName() (3 )

//showName() 1 (3 )

//showName() 2 (3 )

//showName()2 xx(3 )

} //End of class

Documents

Java Programming - Chapter 8 (in Thai)