The following symbols are undefined什么意思在ccs编程中

在CCS编程中，“The following symbols are undefined”意味着编译器找不到某些符号的定义。这通常是由于以下原因之一引起的：

1. 编程文件中缺少某些头文件或库文件，导致编译器无法找到相关的符号定义。

2. 编程文件中存在语法错误或其他错误，使得编译器无法正确解析某些符号。

3. 编程文件中引用了其他库或模块，但是这些库或模块没有正确连接到项目中，导致编译器无法找到相关的符号定义。

要解决这个问题，您可以尝试以下几种方法：

1. 确保所有必要的头文件和库文件都已经包含在项目中，并且路径设置正确。

2. 检查代码中是否存在语法错误或其他错误，并进行修复。

3. 检查项目设置，确保所有必要的库和模块已经正确连接到项目中。

如果您仍然无法解决问题，可以尝试使用调试器或其他工具来定位错误。

相关问题

写一段Java实现Input In the first line you are given the number n of billionaires (1 ≤ n ≤ 10000). The following n lines contain information about these people: their names, cities where they were staying at the beginning of the period, and their fortunes. In the next line you are given the number m of days in the period for which you have the information (1 ≤ m ≤ 50000) and the number k of travels of the billionaires (0 ≤ k ≤ 50000). The following k lines contain the list of travels in the following format: the number of the day (from 1 to m−1), the name of the person, and the city of destination. You may assume that billionaires depart late at night and arrive to the destination city on the next day's morning. They cannot make more than one travel each day. The numbers of days in the list are not decreasing. All names of people and cities consist of at most 20 English letters; you must take into consideration the case of the symbols. The fortunes are in the range from 1 to 100 billions (one billion is a thousand million). Output In each line of the output give the name of a city and, after a space, the number of days during which this city was the first with respect to the sum of fortunes of the billionaires staying there. Leave out those cities for which there were no such days. The cities must be sorted alphabetically (with the usual symbol order: ABC...Zabc...z).

以下是Java实现代码：

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n = scanner.nextInt();
        Map<String, Integer> cityDays = new TreeMap<>();
        Map<String, Integer> cityFortunes = new HashMap<>();
        Map<String, String> billionaireCities = new HashMap<>();

        for (int i = 0; i < n; i++) {
            String name = scanner.next();
            String city = scanner.next();
            int fortune = scanner.nextInt();
            billionaireCities.put(name, city);
            cityFortunes.put(city, cityFortunes.getOrDefault(city, 0) + fortune);
        }

        int m = scanner.nextInt();
        int k = scanner.nextInt();
        for (int i = 0; i < k; i++) {
            int day = scanner.nextInt();
            String name = scanner.next();
            String destCity = scanner.next();
            String origCity = billionaireCities.get(name);
            int fortune = cityFortunes.get(origCity);
            if (cityDays.get(origCity) == null) {
                cityDays.put(origCity, 0);
            }
            if (cityDays.get(destCity) == null) {
                cityDays.put(destCity, 0);
            }
            cityDays.put(origCity, cityDays.get(origCity) + day - cityDays.get(destCity));
            cityDays.put(destCity, day);
            cityFortunes.put(origCity, fortune - cityFortunes.getOrDefault(origCity, 0));
            cityFortunes.put(destCity, cityFortunes.getOrDefault(destCity, 0) + fortune);
            billionaireCities.put(name, destCity);
        }

        List<String> result = new ArrayList<>();
        for (Map.Entry<String, Integer> entry : cityDays.entrySet()) {
            String city = entry.getKey();
            int days = entry.getValue();
            if (days > 0) {
                result.add(city + " " + days);
            }
        }

        for (String s : result) {
            System.out.println(s);
        }
    }
}

解释一下代码：

首先读取输入的数据，使用Map<String, Integer> cityDays记录每个城市的首富天数，Map<String, Integer> cityFortunes记录每个城市的首富总财富，Map<String, String> billionaireCities记录每个亿万富翁所在的城市。

接着，遍历每个亿万富翁，将其所在城市的首富总财富加入到cityFortunes中。然后，读取每个亿万富翁的旅行记录，更新cityDays、cityFortunes和billionaireCities。对于每条旅行记录，先计算出旅行前该亿万富翁所在城市的首富天数，然后将其更新为旅行前最后一次到达该城市的天数减去旅行天数，将目的地城市的首富天数更新为旅行天数，更新原城市和目的地城市的首富总财富，并将该亿万富翁所在城市更新为目的地城市。

最后，遍历cityDays，将首富天数大于0的城市加入到结果列表中，并按照字典序排序输出。

You are to write a lexical analyzer/scanner for the language decaf in java. Goals: 1. The input of the scanner is a source code file and the output of the scanner is a stream of tokens. 2. Your scanner should go for longest possible match i.e. a string ‘:=’is to be identified as ‘ass-symbol’ and not as ‘:’and ‘=’. 3. Token is represented as (Kind, Value). We use the following symbols to denote different kinds of tokens KEY denotes reserved words SYM denotes special symbols ID denotes identifiers NUM denotes numeric constants STR denotes string constants 4. Check lexical errors: giving meaning error messages and the lines where errors occur. The kinds of lexical errors are: - Illegal character, that is, scanner may recognize a character that is not in the alphabet of TINY+ - The right bracket of a STRING is lost - The right delimiter of a comment is lost

Sure, I can help you with that! Here's a sample code for a lexical analyzer/scanner for the decaf language in Java:

import java.io.*;
import java.util.*;

public class Scanner {
    private BufferedReader br;
    private char currentChar;
    private int currentLineNum;
    private String currentTokenValue;

    // reserved words
    private static final Map<String, Token.Kind> reservedWords = new HashMap<>();
    static {
        reservedWords.put("class", Token.Kind.CLASS);
        reservedWords.put("extends", Token.Kind.EXTENDS);
        reservedWords.put("static", Token.Kind.STATIC);
        reservedWords.put("void", Token.Kind.VOID);
        reservedWords.put("main", Token.Kind.MAIN);
        reservedWords.put("public", Token.Kind.PUBLIC);
        reservedWords.put("private", Token.Kind.PRIVATE);
        reservedWords.put("int", Token.Kind.INT);
        reservedWords.put("boolean", Token.Kind.BOOLEAN);
        reservedWords.put("if", Token.Kind.IF);
        reservedWords.put("else", Token.Kind.ELSE);
        reservedWords.put("while", Token.Kind.WHILE);
        reservedWords.put("return", Token.Kind.RETURN);
        reservedWords.put("true", Token.Kind.TRUE);
        reservedWords.put("false", Token.Kind.FALSE);
        reservedWords.put("this", Token.Kind.THIS);
        reservedWords.put("new", Token.Kind.NEW);
    }

    // special symbols
    private static final Map<String, Token.Kind> specialSymbols = new HashMap<>();
    static {
        specialSymbols.put("(", Token.Kind.LPAREN);
        specialSymbols.put(")", Token.Kind.RPAREN);
        specialSymbols.put("{", Token.Kind.LBRACE);
        specialSymbols.put("}", Token.Kind.RBRACE);
        specialSymbols.put("[", Token.Kind.LBRACKET);
        specialSymbols.put("]", Token.Kind.RBRACKET);
        specialSymbols.put(".", Token.Kind.DOT);
        specialSymbols.put(",", Token.Kind.COMMA);
        specialSymbols.put(";", Token.Kind.SEMICOLON);
        specialSymbols.put("=", Token.Kind.ASSIGN);
        specialSymbols.put("!", Token.Kind.NOT);
        specialSymbols.put("&", Token.Kind.AND);
        specialSymbols.put("|", Token.Kind.OR);
        specialSymbols.put("<", Token.Kind.LT);
        specialSymbols.put(">", Token.Kind.GT);
        specialSymbols.put("==", Token.Kind.EQUAL);
        specialSymbols.put("!=", Token.Kind.NOTEQUAL);
        specialSymbols.put("<=", Token.Kind.LE);
        specialSymbols.put(">=", Token.Kind.GE);
        specialSymbols.put("+", Token.Kind.ADD);
        specialSymbols.put("-", Token.Kind.SUB);
        specialSymbols.put("*", Token.Kind.MUL);
        specialSymbols.put("/", Token.Kind.DIV);
        specialSymbols.put("%", Token.Kind.MOD);
    }

    public Scanner(String filename) throws IOException {
        br = new BufferedReader(new FileReader(filename));
        currentLineNum = 1;
        currentChar = (char) br.read();
    }

    private void getNextChar() throws IOException {
        if (currentChar == '\n') {
            currentLineNum++;
        }
        currentChar = (char) br.read();
    }

    private boolean isWhitespace(char c) {
        return c == ' ' || c == '\t' || c == '\r' || c == '\n';
    }

    private boolean isDigit(char c) {
        return c >= '0' && c <= '9';
    }

    private boolean isLetter(char c) {
        return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
    }

    private boolean isLegalCharacter(char c) {
        return isWhitespace(c) || isDigit(c) || isLetter(c) || specialSymbols.containsKey(Character.toString(c));
    }

    private void skipWhitespace() throws IOException {
        while (isWhitespace(currentChar)) {
            getNextChar();
        }
    }

    private Token scanIdentifierOrKeyword() throws IOException {
        StringBuilder sb = new StringBuilder();
        while (isLetter(currentChar) || isDigit(currentChar) || currentChar == '_') {
            sb.append(currentChar);
            getNextChar();
        }
        String tokenValue = sb.toString();
        Token.Kind kind = reservedWords.getOrDefault(tokenValue, Token.Kind.ID);
        return new Token(kind, tokenValue, currentLineNum);
    }

    private Token scanNumber() throws IOException {
        StringBuilder sb = new StringBuilder();
        while (isDigit(currentChar)) {
            sb.append(currentChar);
            getNextChar();
        }
        String tokenValue = sb.toString();
        return new Token(Token.Kind.NUM, tokenValue, currentLineNum);
    }

    private Token scanString() throws IOException {
        StringBuilder sb = new StringBuilder();
        getNextChar();
        while (currentChar != '"') {
            if (currentChar == '\n' || currentChar == -1) {
                throw new LexicalException("Unterminated string", currentLineNum);
            }
            sb.append(currentChar);
            getNextChar();
        }
        getNextChar();
        return new Token(Token.Kind.STR, sb.toString(), currentLineNum);
    }

    private Token scanComment() throws IOException {
        getNextChar();
        getNextChar();
        while (!(currentChar == '*' && br.read() == '/')) {
            if (currentChar == '\n') {
                currentLineNum++;
            }
            getNextChar();
        }
        getNextChar();
        return getNextToken();
    }

    private Token scanSpecialSymbol() throws IOException {
        StringBuilder sb = new StringBuilder();
        while (specialSymbols.containsKey(sb.toString() + currentChar)) {
            sb.append(currentChar);
            getNextChar();
        }
        String tokenValue = sb.toString();
        Token.Kind kind = specialSymbols.get(tokenValue);
        if (kind == null) {
            throw new LexicalException("Illegal character: " + tokenValue, currentLineNum);
        }
        return new Token(kind, tokenValue, currentLineNum);
    }

    public Token getNextToken() throws IOException {
        while (isWhitespace(currentChar)) {
            skipWhitespace();
        }
        if (currentChar == -1) {
            return new Token(Token.Kind.EOF, "", currentLineNum);
        }
        if (!isLegalCharacter(currentChar)) {
            throw new LexicalException("Illegal character: " + currentChar, currentLineNum);
        }
        if (currentChar == '/') {
            getNextChar();
            if (currentChar == '/') {
                while (currentChar != '\n' && currentChar != -1) {
                    getNextChar();
                }
                return getNextToken();
            } else if (currentChar == '*') {
                return scanComment();
            } else {
                return new Token(Token.Kind.DIV, "/", currentLineNum);
            }
        }
        if (isLetter(currentChar)) {
            return scanIdentifierOrKeyword();
        }
        if (isDigit(currentChar)) {
            return scanNumber();
        }
        if (currentChar == '"') {
            return scanString();
        }
        if (specialSymbols.containsKey(Character.toString(currentChar))) {
            return scanSpecialSymbol();
        }
        throw new LexicalException("Illegal character: " + currentChar, currentLineNum);
    }

    public static class LexicalException extends RuntimeException {
        private int lineNum;

        public LexicalException(String message, int lineNum) {
            super(message);
            this.lineNum = lineNum;
        }

        public int getLineNum() {
            return lineNum;
        }
    }
}

This code reads in a source code file and returns a stream of tokens. It uses a map to store the reserved words and special symbols, and uses a series of `if` statements to determine what kind of token it is dealing with. It also handles lexical errors by throwing a `LexicalException` with a meaningful error message and the line number where the error occurred.