/*class Person{
int age;
}
public class Main {
public static void main(String[] args) {
//Person p = new Person();
//Person 클래스로 객체 10개를 만들고싶다.
Person[] p = new Person[10]; //레퍼런스변수의 배열 생성
for(int i=0;i<p.length;i++)
p[i] = new Person(); // 각 객체 생성
Person[] s = new Person[5];
s[2].age=10;
}
}
class Circle{
int radius;
public Circle(int radius) {
this.radius=radius;
}
public double getArea() {
return 3.14*radius*radius;
}
}
public class Main{
public static void main(String[] args) {
Circle[] c;
c=new Circle[5];
for(int i=0;i<c.length;i++)
c[i]=new Circle(i);
for(int i=0;i<c.length;i++)
System.out.println((int)(c[i].getArea())+" ");
}
}
import java.util.*;
class Book{
String title,autor;
public Book(String title,String author) {
this.title=title;
this.autor=author;
}
}
public class Main{
public static void main(String[] args) {
Book[] book=new Book[2];
Scanner sc=new Scanner(System.in);
for(int i=0;i<book.length;i++) {
System.out.print("제목>>");
String title=sc.nextLine();
System.out.print("저자>>");
String author=sc.nextLine();
book[i]=new Book(title,author);
}
for(int i=0;i<book.length;i++)
System.out.print("("+book[i].title+", "+book[i].autor+")");
}
}
접근지정자 :
public - 다른 어떤 클래스에서도 이 필드, 생성자, 메소드 등등 을 접근 가능하다
private - 현재 해당 클래스에서만 접근이 가능하다
import java.util.*;
class Circle{
static int num=0;
private double x,y;
private int radius;
public Circle() {}
public Circle(double x,double y,int radius) {
this.x=x;
this.y=y;
this.radius=radius;
}
static void setNum(int n) { //static 메소드에서는 static 필드만 접근이 가능하다.
//x=1.0;
num=n;
}
// setter getter method
public void setX(double x) {
this.x = x;
}
public void show() {
System.out.println("("+x+","+y+")"+radius);
}
}
public class Main{
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
Circle[] c=new Circle[3];
for(int i=0;i<c.length;i++) {
System.out.print("x, y, radius >>");
double x=scanner.nextDouble();
double y=scanner.nextDouble();
int radius=scanner.nextInt();
c[i]=new Circle(x,y,radius);
}
//c[1].x=10;
//c[1].setX(10);
for(int i=0;i<c.length;i++)
c[i].show();
Circle a = new Circle();
a.num = 100;
Circle b = new Circle();
b.num++;
//static :클래스 마다 생성 (같은 클래스로 만들어진 객체들이 공유하는)
Circle.num=50;
Circle.setNum(5);
scanner.close();
}
}
class Staticsample{
public int n;
public void g() {
m=20;
}
public void h() {
m=30;
}
public static int m;
public static void f() {
m=5;
}
}
public class Main{
public static void main(String[] args) {
Staticsample s1,s2;
s1=new Staticsample();
s1.n=5;
s1.g();
s1.m=50;
s2=new Staticsample();
s2.n=8;
s2.h();
s2.f();
System.out.println(s1.m);
}
}
class StaticSample{
public int n;
public void g() {
m=20;
}
public void h() {
m=30;
}
public static int m;
public static void f() {
m=5;
}
}
public class Main{
public static void main(String[] args) {
StaticSample.m=10;
StaticSample s1;
s1=new StaticSample();
System.out.println(s1.m);
s1.f();
StaticSample.f();
}
}
class Calc{
public static int abs(int a) { return a>0?a:-a;}
public static int max(int a,int b) {return (a>b)?a:b;}
public static int min(int a,int b) {return (a>b)?b:a;}
}
public class Main{
public static void main(String[] args) {
System.out.println(Calc.abs(-5));
System.out.println(Calc.max(10, 8));
System.out.println(Calc.min(-3, -8));
}
}
import java.util.*;
class CurrencyConverter{
private static double rate;
public static double toDollar(double won) {
return won/rate;
}
public static double toKWR(double dollar) {
return dollar*rate;
}
public static void setRate(double r) {
rate = r;
}
}
public class Main{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.print("환율(1달러)>> ");
double rate=sc.nextDouble();
CurrencyConverter.setRate(rate);
System.out.println("백만원은 |"+CurrencyConverter.toDollar(1000000)+"입니다.");
System.out.println("\100는 "+CurrencyConverter.toKWR(100)+"원입니다.");
sc.close();
}
}
1.인스턴스 멤버
2.static 메소드는 static 필드만 접근 가능하다.
3.this 삭제 스태틱이여서
public class Main{
static int s;
static int t;
public static void main(String[] args) {
Main.t=10;
Main.s=20;
Main obj=new Main();
obj.s=30;
obj.t=40;
System.out.println(obj.s);
System.out.println(obj.t);
}
}
import java.util.*;
class Circle{
private double x,y;
int radius;
public Circle(double x,double y,int radius) {
this.x=x;
this.y=y;
this.radius=radius;
}
public void show() {
System.out.println("("+x+","+y+")"+radius);
}
}
public class Main{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
Circle[] c=new Circle[3];
for(int i=0;i<c.length;i++) {
System.out.print("x,y,radius >>");
double x=sc.nextDouble();
double y=sc.nextDouble();
int radius=sc.nextInt();
c[i]=new Circle(x,y,radius);
}
int q=0;
int a=0;
for(int i=0;i<c.length;i++)
{
if(a<c[i].radius) {
a=c[i].radius;
q=i;
}
}
c[q].show();
sc.close();
}
}
import java.util.*;
class Day{
private String work;
public void set(String work) {this.work=work;}
public String get() {return work;}
public void show() {
if(work==null) System.out.println("없습니다. ");
else System.out.println(work+"입니다.");
}
}
public class Main{
public static void main(String[] args) {
System.out.println("이번달 스케쥴 관리 프로그램");
Day[] april=new Day[31];
for(int i=1;i<=30;i++) {
april[i]=new Day();
}
Scanner sc=new Scanner(System.in);
for(int i=0;i<100;i++) {
System.out.print("할일(입력:1,보기:2,끝내기:3)>>");
int num=sc.nextInt();
if(num==1) {
System.out.print("날짜(1~30)?");
int date=sc.nextInt();
System.out.print("할일(빈칸없이 입력)?");
String work=sc.next();
april[date].set(work);
}
else if(num==2) {
System.out.print("날짜(1~30)?");
int date=sc.nextInt();
System.out.print(date+"일의 할 일은");
april[i].show();
}
else {
System.out.println("프로그램을 종료합니다.");
break;
}
}
}
}
*/
import java.util.*;
class Phone{
private String name;
private int numa;
private int numb;
public void set(String name) {
this.name=name;
}
public void numa(int a) {
this.numa=a;
}
public void numb(int b) {
this.numb=b;
}
public void show() {
System.out.println(name+"의 번호는 "+numa+"-"+numb);
}
}
public class Main{
public static void main(String[] args) {
Scanner sc=new Scanner(System.in);
System.out.print("인원수>>");
int member=sc.nextInt();
Phone[] book=new Phone[member];
for(int i=0;i<book.lengthl;i++) {
book[i]=new Phone();
}
for(int i=0;i<book.length;i++) {
System.out.println("이름과 전화번호(이름과 번호는 빈칸없이 입력)>>>");
String name=sc.next();
int a=sc.nextInt();
String l=sc.next();
int b=sc.nextInt();
}
}
}
import java.util.*;
class Day{
private String work;
public void set(String work) {this.work=work;}
public String get() {return work;}
public void show() {
if(work==null) System.out.println("없습니다. ");
else System.out.println(work+"입니다.");
}
}
public class Main{
Day[] d;
public Main(int x) {
d = new Day[x];
for(int i=1;i<=x;i++) {
d[i]=new Day();
}
}
public static void input() {
}
public static void view() {
}
public static void finish() {
}
public static void run() {
while(true) {
System.out.print("할일(입력:1,보기:2,끝내기:3)>>");
int num=sc.nextInt();
if(num==1) {
System.out.print("날짜(1~30)?");
int date=sc.nextInt();
System.out.print("할일(빈칸없이 입력)?");
String work=sc.next();
april[date].set(work);
}
else if(num==2) {
System.out.print("날짜(1~30)?");
int date=sc.nextInt();
System.out.print(date+"일의 할 일은");
april[i].show();
}
else {
System.out.println("프로그램을 종료합니다.");
break;
}
}
}
public static void main(String[] args) {
System.out.println("이번달 스케쥴 관리 프로그램");
Scanner sc=new Scanner(System.in);
Main april = new Main(31);
april.run();
}
}