1. 기본 입출력

import java.util.Scanner;

입력할때

Scanner Input = new Scanner(system.in);

int a = Input.nextInt();    // int형 입력받을때

string b = Input.next();   // string형 입력받을때

double c = Input.nextDouble();  // double형 입력받을때

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출력갈때

System.out.print(" ");

System.out.println(" ");            // ln은 줄바꿈 기능