*13일차 실습

[문제 2] non-static

package com.oop.method.nonstatic;

public class NonStaticSample {

//1. 반환값 없고 매개변수 없는 메소드
//실행 요청시 1~45까지의 임의의 정수 6개 중복되지 않게 발생시켜 출력하는 메소드
//메소드명 : printLottoNumbers


//2. 반환값 없고 매개변수 있는 메소드
//실행 요청시 정수 하나, 문자 하나를 전달받아 문자를 정수 갯수만큼 출력하는 메소드
//메소드명 : outputChar


//3. 반환값 있고 매개변수 없는 메소드
//실행 요청시 알파벳 범위의 임의의 영문자를 하나 발생시켜 리턴하는 메소드
//메소드명 : alphabet


//4. 반환값 있고 매개변수 있는 메소드
//실행 요청시 문자열과 시작인덱스, 끝인덱스를 전달받아 해당 인덱스 범위의 문자열을
//추출하여 리턴하는 메소드. 단 문자열은 반드시 값이 있어야함. 없으면 null 리턴처리
//메소드명 : mySubstring

}

 

 

 

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package kh.java.oop.method.nonstatic;

import java.lang.*;
import java.util.Random;
import java.util.Scanner;

public class NonStaticSample {

	Scanner sc = new Scanner(System.in);

	public void printLottoNumbers() {
		int arr[] = new int[6];

		for (int i = 0; i < arr.length; i++) {
			arr[i] = (int) (Math.random() * 45 + 1); // 1~45
			for (int j = 0; j < i; j++) {
				if (arr[i] == arr[j])
					i--;
			}

		}
		System.out.print("랜덤 수: ");
		System.out.print("[");
		for (int i = 0; i < arr.length; i++) {
			System.out.print(arr[i] + " ");
		}
		System.out.println("]");
		System.out.println();
	}

	public void outputChar(char ch, int n) {
		System.out.print("정수 입력: ");
		n = sc.nextInt();
		System.out.print("문자 입력:  ");
		ch = sc.next().charAt(0);

		System.out.print("[");
		for (int i = 0; i < n; i++) {
			System.out.print(ch + " ");
		}
		System.out.println("]");
		System.out.println();
	}

	public char alphabet() {
		char ch='0';
		int num=(int)(Math.random()*2+1);
		switch(num) {
		case 1:
			ch =(char)(Math.random() * ( (90-65)+1)+65); //대문자
			System.out.print(ch);
			break;
		
		case 2:
			ch =(char)(Math.random() * ( (122-97)+1)+97); //소문자
			System.out.print(ch);
			break;
		}
		System.out.println();
		return ch;
	}


	public String mySubstring(String str, int a, int b) {
		char arr[] = new char[str.length()];

		for (int i = 0; i < str.length(); i++) {
			arr[i] = str.charAt(i);
		}

		for (int i = 0; i < str.length(); i++) {
			if ((i > a && i < b)) {// 시작인덱스~끝 인덱스
				System.out.print(arr[i]);
			} else if (i == a && i == b) {
				System.out.println("null");
			}
		}
		return str;
	}
}

 

 

[문제 3] static

public class StaticMethod {

//static method
//1. 전달한 문자열을 모두 대문자로 바꾸는 static 메소드
//메소드명 : toUpper(String) : String


//2. 문자열(1)에서 전달받은 인덱스(2)의 문자를 전달받은 문자(3)로 변경하는 static 메소드
//메소드명 : setChar(String, int, char) : String


//3. 전달한 문자열에서 영문자의 개수를 리턴하는 static 메소드
//메소드명 : getAlphabetLength(String) : int


//4. 전달한 문자열값을 하나로 합쳐서 리턴 
//메소드명 : concat(String, String) : String
}

 

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package kh.java.oop.method.static_;

public class StaticMethod {
	
	public static String toUpper(String s) {
		return s.toUpperCase();
	}
	
	public static String _setChar(String str, int i ,char ch) {
//		char[]arr = new char[str.length()];
		char[]arr = str.toCharArray();
		arr[i] = ch;
		return new String(arr);
	}
	
	public static String setChar(String str, int i , char ch) {
		//index이전
		//index가 2인경우 0~1읽어서 문자열로 반환
		String before = str.substring(0,i);
		System.out.println("before =  "+before );
		//index이후 문자열
		String after = str.substring(i+1);
		System.out.println("after =  "+after );
		
		return before + ch + after;
	}
	
	public static int getAlphabetLength(String s) {
		return s.length();
	}
	
	public static String Concat(String s1,String s2) {
		return s1+s2;
	}
	
}