IT의 신

package asser; public class Product { public double applyDiscount(double price) { assert(price>0); return price*0.50; } public static void main(String[] args) { Product p=new Product(); double newPrice=p.applyDiscount(Double.parseDouble(args[0])); System.out.println("New Price: "+newPrice); } } the command: java Product 0 What is the result? 출력: New Price: 0.0 해설: the command haven't -ea 즉 자바 실행..

package console; import java.io.Console; public class Console107 { public static void main(String[] args) { Console console=System.console(); char[] pass=console.readPassword("Enter password"); String password=new String(pass); System.out.println(password); } } 결과는? 이클립스에서 실행해보면 Exception in thread "main" java.lang.NullPointerException at console.Console107.main(Console107.java:6) 이렇게 나온다. 컴파일시에..

Node.js와 NPM 설치 https://nodejs.org Create-React-App 설치 npm install -g create-react-app visual studio code 설치 start https://code.visualstudio.com React 프로젝트 생성 npx create-react-app project_name C:\ReactProject>npx create-react-app reactday1 cd reactday1 npm start 프로젝트 실행 npm start http://localhost:3000