2018-11-11

class Token_stream {
private:
    bool full;
    Token buffer;
public:
    Token_stream();
    Token get();
    void push_back(Token t);
    void ignore(char c); //从Token_stream入手消除错误，在get()之前利用cin跳过分号及其之前的字符;
};
void Token_stream::ignore(char c) {
    if (full&&buffer.kind == 'c') {
        full = false;
        return;
    }
    full = false;
    char ch = '0';
    while (cin >> ch) {
        if (ch == c)  //c也将被跳过;
            return;
    }
}