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Java
  • 자바의 역사
  • Ch1
    • Before Start Java
      • History of Java
      • Feature of Java
      • API Documentation
      • Hello World!
      • eclipse shortcut
      • Eclipse IDE
      • GitHub to eclipse
  • Ch2
    • Variable
      • Variable
    • Variable Type
    • Character and String
    • Primitive type and range
    • printf and formatter
    • Scanner
    • Overflow of Int
    • Transition between different variable types
    • Object Array
  • CH3
    • Operator
  • CH4
    • 조건문과 반복문
    • if statement
    • switch
    • Math.random()
    • for statement
    • while statement
    • break, continue, named iterated statement
  • CH5
    • Array
    • 배열 활용
    • String Array
  • OOP
    • Intro
  • Class and Object
  • Make multiple Classes in one file
  • How to use Object
  • Object Array
  • Variable type according to declared location
  • Class Variable and Instance Variable
  • Method
  • Call Stack
  • Parameter
  • Static method(Class method) and Instance method
  • (Method)Overloading
  • Constructor
  • Constructor this()
  • Reference type variable "this"
  • Initialize variable
  • Inheritance
  • Composite
  • Single Inheritance, Object Class
  • (Method)Overriding
  • super, super()
  • package, class path
  • import, static import
  • modifier
  • access modifier
  • Encapsulation
  • Polymorphism
  • reference type transition
  • instanceof operator
  • Parameter polymorphism
  • Multiple object using one array
  • Abstract Class, Abstract Method
  • Creating Abstract Class
  • Interface
  • Interface Polymorphism
  • Interface Pros
  • Default method and static method
  • Inner Class
  • Anonymous Class
  • java.lang package and useful class
    • Object class
    • hashCode(), toString()
    • String class
    • StringBuffer class
    • StringBuilder class
    • Math class
    • Wrapper class
    • Number class
    • String to Number, String to Wrapper class
    • Auto-boxing and (auto)Unboxing
  • Collection Framework
    • Collections framework
    • List, Set, Map Interface
    • List의 removeAll() 과 clear() 비교
    • List Interface - ArrayList
    • How to view Java API source
    • List Interface - LinkedList
    • Stack and Queue
    • Iterator, ListIterator, Enumeration
    • Array
    • Comparator와 Comparable
    • Stack
    • String
    • String + char = String
    • String.toCharArray()
    • BufferedReader / BufferWriter
    • Scanner로 String 입력 - next( )와 nextLine( )
    • 공백없이 2차원배열 데이터 String으로 한번에 한줄씩 입력받기(문자/숫자)
    • 공백을 사이에 두고 빠른 2차원 배열 입출력
    • arr[index++]과 arr[index] index++의 차이
    • int와 long의 차이
    • Untitled
    • 타입 간의 변환
    • Array 와 ArrayList
    • valueOf()
    • Char
    • 변수, 객체 초기화(초기값 설정)
  • error troubleshooting
    • No enclosing instance of type
    • ASCII Code Table
    • java.lang.NumberFormatException
    • No enclosing instance..
  • reference
    • String을 생성하는 2가지 방법과 차이점
    • StackOverflowError(스택, 힙 메모리)
    • swtich-case 반복문
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  1. CH5

배열 활용

  1. 배열의 요소 중에서 최대값과 최소값 찾기

class Ex5_3 { 
	public static void main(String[] args) { 
		int[] score = { 79, 88, 91, 33, 100, 55, 95 }; 

		int max = score[0]; 
		int min = score[0]; 

		for(int i=1; i < score.length;i++) {
			if(score[i] > max) { 
				max = score[i]; 
			} else if(score[i] < min) { 
				min = score[i]; 
			} 
		} // end of for 

		System.out.println("최대 :" + max);       
		System.out.println("최소 :" + min);       
	} // end of main 
} // end of class

2. shuffle(섞기) : 숫자 섞기, 로또번호 생성

class lottery {
	public static void main(String[] args) {
		int[] ball = new int[45];//45개의 정수값을 저장하기 위한 int타입의 배열을 만들어준다.
		
		//배열의 각 요소에 1~45의 값을 저장한다.
		for(int i=0; i < ball.length; i++) {
			ball[i] = i+1;
		}
		
		int tmp = 0;
		int index = 0;
		
		//6개의 로터리 번호를 생성해보자!
		for(int i=0; i < 6;i++) {
//			index = Math.random()*(ball.length);
			index = (int)(Math.random()*45);//배열의 index인 0부터 44사이의 랜덤한 수 생성!
			tmp = ball[i];
			ball[i] = ball[index];
			ball[index] = tmp;
		}
		
		for(int i = 0; i <6;i++) {
			System.out.printf("ball[%d] = %d%n",i,ball[i]);
		}
	}
}

PreviousArrayNextString Array

Last updated 4 years ago

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