interpreter.h

这是清华出的这本经典的数据结构第三版上的随书例子。希望对大家有用。

//**************************  interpreter.h   ***********************

#ifndef INTERPRETER
#define INTERPRETER

#include <iostream>
#include <list>
#include <algorithm> // find()

using namespace std;

class IdNode {
public:
    IdNode(char *s = "", double e = 0) {
        id = strdup(s);
        value = e;
    }
    bool operator== (const IdNode& node) const {
        return strcmp(id,node.id) == 0;
    }
private:
    char *id;
    double value;
    friend class Statement;
    friend ostream& operator<< (ostream& out, const IdNode& r) {
        out << r.id << " = " << r.value << endl;
        return out;
    }
};

class Statement {
public:
    Statement() { 
    }
    void getStatement();
private:
    list<IdNode> idList;
    char  ch;
    double factor();
    double term();
    double expression();
    void readId(char*);
    void issueError(char *s) { 
        cerr << s << endl; exit(1); 
    }
    double findValue(char*);
    void  processNode(char*, double);
    friend ostream& operator<< (ostream& out, const Statement& s) {
        list<IdNode>::const_iterator i = s.idList.begin();
        for ( ; i != s.idList.end(); i++)
            out << *i;
        out << endl;
        return out;
    }
};

#endif