JAVA 기본 문법

출력

  

    
    
    
    
  
public class Hello2030 {
	public static void main(String [] args) {
		int n=2030;
		System.out.print("헬로"+n);
	}
}

print()는 줄바꿈없이 계속 출력, println()는 개행(한 문장 출력후 다음줄로 넘어감)

  

    
    
    
    
  
public class MyInfoApp {
	public static void main(String [] args) {
		System.out.println("Kitae Hwang");
		System.out.println("20 years old");
		System.out.println("Department of Computer Engineering");
		
	}
}

---

자료형

기본 자료형에는 

  

    
    
    
    
  
public class Pi {
	public static void main(String[] args) {
		final double PI=3.14;
		
		double radius=10.0;
		double circleArea=radius*radius*PI;
		
		System.out.println("원의면적 ="+circleArea);
}
}

형변환 (type casting)

  

    
    
    
    
  
package casting;

public class casting {
	public static void main(String[] args) {
		byte b=127;
		int i=100;
		System.out.println(b+i);
		System.out.println(10/4);
		System.out.println(10.0/4);
		System.out.println((char)0x12340041);
		System.out.println((byte)(b+i));
		System.out.println((int)2.9+1.8);
		System.out.println((int)(2.9+1.8));
		System.out.println((int)2.9+(int)1.8);
	}
}

---

scanner 활용

  

    
    
    
    
  
import java.util.Scanner;

public class ScannerEx {
	public static void main(String args[]) {
		System.out.println("이름, 도시, 나이, 체중, 독신 여부를 빈칸으로 분리하여 입력하세요");
		Scanner scanner = new Scanner(System.in);

		String name = scanner.next();
		System.out.print("이름은 " +name+",");
		String city = scanner.next();
		System.out.print("도시는 " +city+",");
		int age = scanner.nextInt();
		System.out.print("나이는 " +age+"살");
		double weight = scanner.nextDouble();
		System.out.print("체중은 " +weight+"kg,");
		boolean isSingle = scanner.nextBoolean();
		System.out.println("독신 여부는  " +isSingle+"입니다.");
		
		scanner.close();
	}
}