클래스 - (Day01)

메소드 #1

package day01.ex03_Class;

class ClaMeth {		
	
	int zz = 123;	// 멤버변수
	String a = "에이맨";
	
	void meth_1() {
		int x = 11;	// 지역변수  - 구간 내부에서만 사용가능
		System.out.println("meth_1() 실행 param X, ret X : " + x + "," + "zz : " + zz);
		x++;		// 증가가 안되는게 아닌 사라지는 것
		zz++;
	}
	
	void meth_2(String a, int b) {
		// 매개변수도 지역변수이다.
		// String a = "에이맨"; 매개변수와 지역변수는 충돌 발생
		System.out.println("meth_2() 실행 param O, ret X :" + a + "," + b);
	}
	
	int meth_3() {
		System.out.println("meth_3() 실행 param X, ret O");
		return 100;
	}

	int meth_4(String a, int b) {
		System.out.println("meth_4() 실행 param O, ret O " + a + "," + b + ", " + this.a);
		return 200;
	}
	
	
}


public class MethodMain {

	public static void main(String[] args) {
		ClaMeth cm = new ClaMeth();
		
		// void r1 =
		cm.meth_1();
		cm.meth_1();
		cm.meth_2("아기상어", 1234);
		int r3 = cm.meth_3();
		int r4 = cm.meth_4("아빠상어", 4567);
		

		System.out.println(r3);
		System.out.println(r4);
		
	}
}

 

클래스 #1

package day01.ex03_Class;

class AAA {			// 클래스의 정의
	
	int a = 10;		// 멤버 변수
	
	void meth_1() {	// 멤버 메소드
		
		System.out.println("AAA meth_1() 실행");
	}
}

public class ClassMain {
	public static void main(String[] args) {
		
		AAA a1;	// 인스턴스 변수 선언
		a1 = new AAA();

		AAA a2 = new AAA();
		a2.a = 1111;
		
		System.out.println("a1.a : " + a1.a);
		a1.meth_1();
		
		System.out.println("a2.a : " + a2.a);
		a2.meth_1();
		
		
	}
}

클래스 #2

 

package day01.ex03_Class;

//멤버 변수를 중요시

class Stud {
	
	String name, ttt;
	int [] jum ;
	int tot, avg;
	
}


public class StudMain {
	public static void main(String[] args) {
		Stud st1 = new Stud();
		Stud st2 = new Stud();
		Stud st3 = new Stud();
		Stud st4 = new Stud();
		Stud st5 = new Stud();

		st1.name = "현빈";
		st1.jum = new int[]{78, 79, 81};
		st2.name = "원빈";
		st2.jum = new int[]{58, 59, 51};
		st3.name = "장희빈";
		st3.jum = new int[]{98, 99, 91};
		st4.name = "커피빈";
		st4.jum = new int[]{68, 69, 61};
		st5.name = "젤리빈";
		st5.jum = new int[]{88, 89, 81};
		
		// 새로 공간에 만들려면 반드시 new가 필요함
		
//		int[] arr;
//		arr = new int[] {11,22,33};
		
		st1.ttt = st1.name + "\t";
		
		for (int i : st1.jum) {
			st1.tot += i;
			st1.ttt += i + "\t";
		}
		st1.avg = st1.tot/st1.jum.length;
		st1.ttt += st1.tot + "\t" + st1.avg;
				
		System.out.println(st1.ttt);
		
		st2.ttt = st2.name + "\t";
		
		for (int i : st2.jum) {
			st2.tot += i;
			st2.ttt += i + "\t";
		}
		st2.avg = st2.tot/st2.jum.length;
		st2.ttt += st2.tot + "\t" + st2.avg;
		
		System.out.println(st2.ttt);
		
		st3.ttt = st3.name + "\t";
		
		for (int i : st3.jum) {
			st3.tot += i;
			st3.ttt += i + "\t";
		}
		st3.avg = st3.tot/st1.jum.length;
		st3.ttt += st3.tot + "\t" + st3.avg;
		
		System.out.println(st3.ttt);
		
		st4.ttt = st4.name + "\t";
		
		for (int i : st4.jum) {
			st4.tot += i;
			st4.ttt += i + "\t";
		}
		st4.avg = st4.tot/st4.jum.length;
		st4.ttt += st4.tot + "\t" + st4.avg;
		
		System.out.println(st4.ttt);
		
		st5.ttt = st5.name + "\t";
		
		for (int i : st5.jum) {
			st5.tot += i;
			st5.ttt += i + "\t";
		}
		st5.avg = st5.tot/st5.jum.length;
		st5.ttt += st5.tot + "\t" + st5.avg;
		
		System.out.println(st5.ttt);
	}
}

 

mp3 클래스

 

package day01.ex04_mp3;


class MP3_1 {
	void MP3_1(String s1) {
		System.out.println(s1 + " : " + "음악을듣고, 라디오를 들어요");
	}
}


class MP3_2 {
	void MP3_2(String s2) {
		System.out.println(s2 + " : " + "음악을 듣고, 녹음을 해요");
	}
	
}

class MP3_3 {
	void MP3_3(String s3) {
		System.out.println(s3 + " : " + "음알을 찾고, 음알을 삭제해요");
	}
}



public class MP3 {
	public static void main(String[] args) {
		MP3_1 m = new MP3_1();
		MP3_2 m2 = new MP3_2();
		MP3_3 m3 = new MP3_3();
		m.MP3_1("트와이스 1집");
		m2.MP3_2("AOA, 소녀시대");
		m3.MP3_3("홍진영");
		
	}
}

배열복습

package day01.ex03_Class;

class StudArr2{
	
	String name,ttt;
	int [] jum ;
	int tot;
	double avg;
}

public class StudArrayMain2 {

	public static void main(String[] args) {
		
		String [] arr2 = new String[5];
		
		arr2[0] = "이효리";
		
		//StudArr [] arr = new StudArr[5];
//		StudArr [] arr = {
//				new StudArr(),new StudArr(),new StudArr(),
//				new StudArr(),new StudArr()
//		};
		
		StudArr [] arr = new StudArr[5];
		
		for (int i = 0; i < arr.length; i++) {
			arr[i] = new StudArr();
		}
		
//		for (StudArr st : arr) {
//			st = new StudArr();
//		}

		///1. 입력부
		arr[0].name = "현빈";
		arr[0].jum = new int[]{78,79,81};
		arr[2].name = "원빈";
		arr[2].jum = new int[]{58,59,51};
		arr[3].name = "장희빈";
		arr[3].jum = new int[]{98,99,91};
		arr[4].name = "커피빈";
		arr[4].jum = new int[]{68,69,63};
		arr[1].name = "젤리빈";
		arr[1].jum = new int[]{88,89,81};
		
		String [] index = {"가","가","가","가","가","가","양","미","우","수","수"};		
		///2. 연산부
		for (StudArr st : arr) {
			st.ttt = st.name+"\t";
			
			for (int i : st.jum) {
				st.tot += i;
				st.ttt+=i+"\t";
			}
			st.avg = (double)(int)((double)st.tot/st.jum.length*100+0.5)/100;
			st.ttt+=st.tot+"\t"+st.avg+"\t"+index[(int)st.avg/10];
		}
		
		int temp = 0;
		
		for (int i = 0; i < arr.length; i++) {
			for (int j = i +1; j < arr.length; j++) {
				if(arr[i].tot > arr[j].tot) {
					
					temp = arr[i].tot;
					arr[i].tot = arr[j].tot;
					arr[j].tot = temp;
				}
			}
		}
		///평균 기준 수우미양가 출력하세요
		/*
		 79.33333333333333
		 7933.333333333333
		 7933
		 7933.0
		 79.33
		 */
		
		///3. 출력부
		for (StudArr st : arr) {
			System.out.println(st.ttt + "\t" + st.tot);
		}
		
		
	}

}