I immediately stumbled on the standard input method with AtCoder.

Introduction

I've been working as an engineer until now, but I started doing competition pregramming because I thought it was difficult to implement because it was mainly in the upstream process. I managed to solve one question, but I will post a memorandum of what I stumbled upon.

This time I will write about the data entry Scanner.

Challenged problem

Atcode's past score of 100 problem ... In other words, it's a simple problem.

https://atcoder.jp/contests/abc042/tasks/abc042_a

First submission

I managed to code while looking at various sites, and I was able to execute it from the vscode terminal and get the expected result. The following is the code content (probably a dirty code from an expert's point of view, but please forgive me ...)

public class Main {
    public static void main(String args[]) {
        String answer = "YES";
        String[] haiku = args;
        int sum = 0;
        for(int i = 0; i < 3; i++){
          if(haiku[i].equals("7") || haiku[i].equals("5")){
              sum = sum + Integer.valueOf(haiku[i]);
              System.out.println(sum);
          }
          else{
              answer = "NO";
          }
          System.out.println(haiku[i]);
        } 
        if(sum != 17){
            answer = "NO";
        }
        System.out.println(answer);
    }
}

result

Run-time error ... I couldn't even check the contents ... \ (^ o ^) /

What went wrong

It seems that the input method was simply useless.

When I type Java Main X X X in the terminal, it's stored in the array ʻargs` separated by spaces, so I thought it was okay, but I was completely wrong.

What should i do

It is recommended to use Scanner to get the input contents. Get the input at the next (); part and use it again to get the next input value.

Scanner sc = new Scanner(System.in);
int i = Integer.parseInt(sc.next());

5th submission

I refactored the code many times (I'm sorry I want to use the term ...) and managed to clear it lol

import java.util.Scanner;
public class Main {
    public static void main(String args[]) {
        String answer = "YES";
        Scanner s = new Scanner(System.in);
        int sum = 0;
        for(int i = 0; i < 3; i++){
            int haiku = Integer.parseInt(s.next());
          if(haiku == 7 || haiku == 5 ){
              sum = sum + haiku;
          }
          else{
              answer = "NO";
          }
        } 
        if(sum != 17){
            answer = "NO";
        }
        System.out.println(answer);
    }
}

Reference site

https://qiita.com/p_shiki37/items/a0f6aac33bf60f5f65e4 https://uxmilk.jp/48686