์• ์ •์ฝ”๋”ฉ ๐Ÿ’ป

1. ๋ฌธ์ž ์ฐพ๊ธฐ

ํ•œ๊ฐœ์˜ ๋ฌธ์ž์—ด์„ ์ž…๋ ฅ๋ฐ›๊ณ  ํŠน์ • ๋ฌธ์ž๋ฅผ ์ž…๋ ฅ๋ฐ›์•„ ์ž…๋ ฅ๋ฐ›์€ ๋ฌธ์ž์—ด์— ํŠน์ •๋ฌธ์ž๊ฐ€ ๋ช‡๊ฐœ ์กด์žฌ ํ•˜๋Š” ์ง€ ์•Œ์•„๋‚ธ๋‹ค.

* ๋Œ€์†Œ๋ฌธ์ž๋ฅผ ๊ตฌ๋ถ„ํ•˜์ง€ ์•Š๋Š”๋‹ค.

 


1. ํŠน์ •๋ฌธ์ž 1๊ฐœ๋ฅผ ๋ฐ›์•„ ๋ณ€์ˆ˜์— ๋„ฃ๊ธฐ ์œ„ํ•ด charAt(0)์„ ์‚ฌ์šฉํ–ˆ๋‹ค.

sc.next().charAt(0)

2. Character.toUpperCase() ๋ฅผ ํ†ตํ•ด ํŠน์ •๋ฌธ์ž 1๊ฐœ๋ฅผ ๋Œ€๋ฌธ์ž๋กœ ๋ณ€๊ฒฝํ–ˆ๋‹ค.

3. ํ–ฅ์ƒ๋œ for๋ฌธ ์‚ฌ์šฉ์„ ์œ„ํ•ด String ๋ฌธ์ž์—ด์„ toCharArray() ์„ ์‚ฌ์šฉํ•˜์—ฌ char ๋ฐฐ์—ด๋กœ ๋ณ€๊ฒฝํ–ˆ๋‹ค.

 

import java.util.Scanner;

public class Main {

  public int solution(String str, char ch) {
    int answer = 0;
    str = str.toUpperCase();
    ch = Character.toUpperCase(ch);

//    for (int i = 0; i < str.length(); i++) {
//      if (str.charAt(i) == ch) {
//        answer++;
//      }
//    }
    
    for(char x : str.toCharArray()){
      if(x == ch){
        answer++;
      }
    }
    return answer;
  }

  public static void main(String[] args) {
    Main test1_01 = new Main();
    Scanner scanner = new Scanner(System.in);
    String str = scanner.next();
    char ch = scanner.next().charAt(0);
    System.out.println(test1_01.solution(str, ch));
  }
}

 

2. ๋Œ€์†Œ๋ฌธ์ž ๋ณ€ํ™˜

๋Œ€๋ฌธ์ž, ์†Œ๋ฌธ์ž๊ฐ€ ๊ฐ™์ด ์กด์žฌํ•˜๋Š” ๋ฌธ์ž์—ด์—์„œ ๋Œ€๋ฌธ์ž๋ฅผ ์†Œ๋ฌธ์ž๋กœ ์†Œ๋ฌธ์ž๋ฅผ ๋Œ€๋ฌธ์ž๋กœ ๋ณ€๊ฒฝํ•˜์—ฌ ๋ฌธ์ž์—ด์„ return ํ•œ๋‹ค.


1. ํ•ด๋‹น ๋ฌธ์ž๊ฐ€ ์†Œ๋ฌธ์ž์ธ์ง€ ๋Œ€๋ฌธ์ž์ธ์ง€ ํ™•์ธํ•˜๊ธฐ ์œ„ํ•ด Character.isUppercase() ๋ฅผ ์‚ฌ์šฉํ–ˆ๋‹ค.

 

2. ์•„์Šคํ‚ค์ฝ”๋“œ๋กœ๋„ ๊ตฌํ˜„ ๊ฐ€๋Šฅํ•˜๋‹ค.

 

๋Œ€๋ฌธ์ž๋Š” 65~90, ์†Œ๋ฌธ์ž๋Š” 97~122 ์ด๊ณ  ๋Œ€๋ฌธ์ž์™€ ์†Œ๋ฌธ์ž์˜ ์ฐจ์ด๋Š” 32 ์ด๊ธฐ ๋•Œ๋ฌธ์—

if(x>=64 && x<=90) ์ผ๋•Œ๋Š” ๋Œ€๋ฌธ์ž ์ด๊ณ 

if(x>=97 && x<=122) ์ผ๋•Œ ์†Œ๋ฌธ์ž ์ด๋‹ค.

answer = (char) (x-32);

(char) ๋กœ ํ˜•๋ณ€ํ™˜ ํ•ด์ฃผ๋ฉด ์•„์Šคํ‚ค์ฝ”๋“œ ์ˆซ์ž ๋Œ€๋กœ ๋ฌธ์ž๊ฐ€ return ๋œ๋‹ค.

-32๋ฅผ ํ•ด์ค€ ์ด์œ ๋Š” ์†Œ๋ฌธ์ž์ผ ๊ฒฝ์šฐ ๋Œ€๋ฌธ์ž๋กœ ๋ณ€๊ฒฝ๋˜๊ณ 

+32๋ฅผ ํ•ด์ฃผ๋ฉด ๋Œ€๋ฌธ์ž๊ฐ€ ์†Œ๋ฌธ์ž๋กœ ๋ณ€๊ฒฝ๋œ๋‹ค

 

import java.util.Scanner;

public class Main {

  public String solution(String sentence){
    String result = "";
    for (char x : sentence.toCharArray()) {
      if (Character.isUpperCase(x)) {
        x = Character.toLowerCase(x);
      } else {
        x = Character.toUpperCase(x);
      }
      result =  result + x;
    }
    return result;
  }

  public static void main(String[] args) {
    Main main = new Main();
    Scanner sc = new Scanner(System.in);
    String sentence = sc.next();
    System.out.println(main.solution(sentence));
  }
}
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