[백준 BAEKJOON / 자바 JAVA] 2557번 : Hello World

Q) BAEKJOON / JAVA / 2557 : Hello World

https://www.acmicpc.net/problem/2557

2557번: Hello World

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A)

 - [1] System 클래스 : 표준 입출력

public class Main {
	public static void main(String[] args) {
		System.out.println("Hello World!");
	}
}

 

 - [2] IO 클래스 : 버퍼 입출력

import java.io.BufferedWriter;
import java.io.OutputStreamWriter;
import java.io.IOException;
 
public class Main {
	public static void main(String[] args) throws IOException {
		BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
 
		bw.write("Hello World!");
		bw.flush();
		bw.close();
	}
}

 

 - [3] StringBuilder : 문자열 조작시 유용

public class Main {
	public static void main(String[] args){
 
		StringBuilder sb = new StringBuilder();
		sb.append("Hello World!");
		
		System.out.println(sb);
	}
}

 

 - [4] StringBuffer : 동기화 지원

public class Main {
	public static void main(String[] args){
 
		StringBuffer sb = new StringBuffer();
		sb.append("Hello World!");
		
		System.out.println(sb);
	}
}