JAVAのコンソールログでRPGの作成

Question

学校の課題でコンソールログで動くRPGを作れといわれました
以下のコードなのですが主人公(●)が動きません
どうすれば動ききますか？

import java.util.Scanner;


public class RPG {

	public static void main(String[] args) {
		System.out.println("ｈで左、ｋで右、uで上、ｊでした");
		Scanner sc = new Scanner(System.in);

		Map map = new Map();
		String hero = "主";
		int x = 18;
		int y = 6;
		map.main[x][y] = hero;
		int a = 0;
		do {


		//Map
		for(int i = 0; i < map.main.length; i++){
			for(int j = 0; j < map.main[0].length; j++){
				if(j % 20 == 0){
					System.out.println();
				}else {
					System.out.print(map.main[i][j]);
				}
			}
		}



		System.out.println();
		System.out.println("下に入力");
		String action = sc.next();

		switch(action){

		case "h":
			x--;
			break;

		case "k":
			x++;
			break;

		case "u":
			y++;
			break;

		case "j":
			y--;
			break;

		default:
			break;
		}



	}while( a == 0);

}
}

public class Map {
	
	String[][] main = {{"海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海"},
			{"海","海","山","山","山","山","山","山","山","山","山","山","山","草","草","草","草","草","海","海"},
			{"海","山","山","山","山","山","山","山","山","山","山","山","草","草","草","草","草","草","草","海"},
			{"海","山","山","山","山","山","山","山","山","山","草","草","草","草","草","草","草","草","草","海"},
			{"海","山","山","山","山","山","山","草","草","草","草","草","草","草","草","草","草","草","草","海"},
			{"海","森","森","森","森","森","森","森","森","森","草","草","草","草","草","草","草","草","草","海"},
			{"海","森","森","森","森","森","森","森","森","森","森","草","草","草","草","草","草","草","草","海"},
			{"海","森","森","森","森","森","森","森","森","森","草","草","草","草","草","草","草","草","草","海"},
			{"海","草","森","森","森","森","森","森","森","森","草","草","草","草","草","草","草","草","草","海"},
			{"海","草","草","草","草","草","草","草","草","草","草","草","草","草","草","草","草","草","草","海"},
			{"海","草","草","草","草","城","草","草","草","草","草","草","草","草","草","草","草","草","草","海"},
			{"海","草","草","草","草","道","草","草","草","草","草","草","草","草","草","草","森","森","森","海"},
			{"海","草","草","草","草","道","草","草","草","草","草","草","草","草","草","森","森","森","森","海"},
			{"海","草","草","草","草","道","草","草","草","草","草","草","草","草","草","草","森","森","森","海"},
			{"海","草","草","草","道","道","道","道","道","道","道","道","道","街","草","草","草","草","草","海"},
			{"海","草","草","草","道","草","草","草","草","草","草","草","草","草","草","草","草","草","草","海"},
			{"海","草","草","草","道","草","草","草","草","草","草","草","草","草","草","草","草","草","草","海"},
			{"海","草","草","草","道","草","草","草","草","草","草","草","草","草","草","草","草","草","草","海"},
			{"海","海","草","道","道","道","草","草","草","草","草","草","草","草","草","草","草","草","海","海"},
			{"海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海","海"}};


	


}

Answer 1

初心者らしいバグなので、丁寧めに説明します。

悪くないコードですが、インデントなど調整して少し読みやすくしました。
（個人的な好みもあるので、これが正解ではありません。）
更にコメントをして各々の処理に名前をつけました。

import java.util.Scanner;

public class RPG {
    public static void main(String[] args) {
        // 初期メッセージ
        System.out.println("ｈで左、ｋで右、uで上、ｊでした");
        // 最初のコマンド取得
        Scanner sc = new Scanner(System.in);

        // マップの読み込み
        Map map = new Map();

        // 主人公の位置設定
        String hero = "主";
        int x = 18;
        int y = 6;

        // 主人公をマップに配置
        map.main[x][y] = hero;
        int a = 0;
        // メインループ
        do {    
            //Mapの表示
            for(int i = 0; i < map.main.length; i++){
                for(int j = 0; j < map.main[0].length; j++){
                    if(j % 20 == 0){
                        System.out.println();
                    }else {
                        System.out.print(map.main[i][j]);
                    }
                }
            }

            // 次のコマンド取得
            System.out.println();
            System.out.println("下に入力");
            String action = sc.next();

            // 主人公の位置を更新
            switch(action){
            case "h":
                x--;
                break;

            case "k":
                x++;
                break;

            case "u":
                y++;
                break;

            case "j":
                y--;
                break;

            default:
                break;
            }
        }while( a == 0);

    }
}

ちょっと長くて読みづらいので、大きな制御文とコメントのみにします。

public class RPG {
    public static void main(String[] args) {
        // １、初期メッセージ
        // ２、最初のコマンド取得

        //３，マップの読み込み
        //４，主人公の位置設定
        //５，主人公をマップに配置

        // ６，メインループ
        do {    
            //７，Mapの表示
            // ８，次のコマンド取得
            // ９，主人公の位置を更新
        }while(true);
    }
}

メインループの中で次のコマンドを受け取り（８）、主人公の位置を変更（９）していますが、メインループの外でしか主人公をマップに配置（５）していないので、最初の配置から主人公は移動しません。主人公の配置をメインループに足しましょう（９の後？）。

そうすると、主人公の位置は更新されますが、argiusさんの１で指摘する問題が出ます。

他にも、指摘したいところ、バグありますが、グッと我慢します。一つずつ解決しプログラムが進化する楽しみを奪いたくないからです。バグにあたったらまた、質問を作成して下さい。楽しみにしています。

Comments

[Yoshinori]

丁寧にありがとうございます！！
明日はおそらく台風の影響で学校が休みなのでご指摘していただいた場所の改善に没頭します！

[iwamoto_takaaki]

応援します。

[Yoshinori]

おはようございます・・・。
あられから試行錯誤していろいろ試したらエラーだらけで・・・
なにから手を付けたらいいかもわからなくなりました＞＜
なにをどこにどう書けばいいでしょうか。。。

Answer 2

1. マップに直接主人公を書きこんでしまうと、主人公が移動した後のマップをどうやって元に戻すのかという問題が発生します。

2.map.main[x][y] = hero;というコードは、後からxやyの値を変えても、heroの位置は変わりません。

ループの中で、主人公が居る位置に来た時に、マップの代わりに主人公を出力してあげるようにしてみてください。