코딩테스트 입문

	import java.util.*;
    
    public void test() {
    	int i = 0;
        char ch = 'a';
    	String str = "abc";
        String[] strArr = new String[3];

		// String -> char[]
		char[] chArr = str.toCharArray();
  
  		// length, length()
  		int strArrLen = strArr.length;
        int strLen = str.length();
    	
        // sort()
        Arrays.sort(chArr);
        
        // repeat()
        String repeatedResult = str.repeat(i);
        
        // StringBuilder
        StringBuilder sb = new StringBuilder(str);
        sb.append("def");

		// reverse()
		String reversedResult = sb.reverse().toString();
        
        // 숫자여부, 대소문자
        boolean isDigitCh = Character.isDigit(ch);
        boolean isUpperCase = Character.isUpperCase(ch);
        char toLowerCaseChar = Character.toLowerCase(ch);
        String toUpperCaseStr = str.toUpperCase();
        
        // char -> int
        char charAtResult = str.charAt(i);
        int chToInt = ch - '0';
        
        // 배열 출력
        System.out.println(Arrays.toString(temp));
    }