词法分析

#include <stdio.h>#include <string.h>const int INT=0;const int BOOL = 1;const int VOID = 2;const int TRUE = 3;const int FALSE = 4;const int IF = 5;const int ELSE = 6;const int FOR = 7;const int WHILE = 8;const int CONTINUE = 9;const int BREAK = 10;const int INC = 11;const int DEC = 12;const int ADD = 13;const int SUBTRACT = 14;const int MULTI = 15;const int DIVIDE = 16;const int GT = 17;const int GE = 18;const int LT = 19;const int LE = 20;const int EQ = 21;const int NE = 22;const int AND = 23;const int OR = 24;const int NOT = 25;const int ASSIGN = 26;const int ASSIGN_ADD = 27;const int ASSIGN_SUBTRACT = 28;const int ASSIGN_MULTI = 29;const int ASSIGN_DIVIDE = 30;const int PARENTHESIS_START = 31;const int PARENTHESIS_END = 32;const int BRACE_START = 33;const int BRACE_END = 34;const int COMMA = 35;const int SEMICOLON = 36;const int ID = 37;const int CONST = 38;const int POSITIVE = 39;const int NEGATIVE = 40;const int NONE = 41;char* keywords[]={"int", "bool", "void", "true", "false", "if", "else", "for", "while", "continue", "break",                  "++", "--", "+", "-", "*", "/", ">", ">=", "<", "<=", "==", "!=", "&&", "||", "!",  "=", "+=", "-=", "*=", "/=", "(", ")", "{", "}", ",", ";"};class Token{public:int type, value;char* p_name;Token(int NONE, int value=-1, char* p_name = NULL);void print();~Token();};class BufferedReader{public:const static int BLOCKN = 1024;                  BufferedReader();Token readToken();private:char buffer[BLOCKN+1];    int buffer_off;           char buffer_c;char readChar();void pushChar(char c){buffer_c = c;}bool loadBuffer();Token readOperator();Token readInt();Token readIDOrKey();};Token::Token(int type, int value, char* p_name){this->type = type;this->value = value;this->p_name = p_name;}Token::~Token(){if(p_name != NULL) delete[] p_name;}void Token::print(){for(int i = 0; i <= 10; i++){if(type == i){printf("<keyword, %s>\n", keywords[i]);return;}}for(int i = 11; i <= 36; i++){if(type == i){printf("<operator, %s>\n", keywords[i]);return;}}if(type == ID){printf("<ID, %s>\n", p_name);}else if(type == CONST){printf("<const, %d>\n", value);}}bool BufferedReader::loadBuffer(){if(fgets(buffer, BufferedReader::BLOCKN, stdin) == NULL)return false;buffer_off = 0;return true;}BufferedReader::BufferedReader(){buffer[buffer_off=0] = 0;buffer_c = 0;}char BufferedReader::readChar(){if(buffer_c != 0){char ch = buffer_c;buffer_c = 0;return ch;}if(buffer[buffer_off] == 0 && !loadBuffer())return EOF;return buffer[buffer_off++];}Token BufferedReader::readOperator(){char ch1 = readChar();char ch2;switch(ch1){case '+':ch2 = readChar();if(ch2 == '+')return Token(INC);else if(ch2 == '=')return Token(ASSIGN_ADD);else{putchar(ch2);return Token(ADD);}case '-':ch2 = readChar();if(ch2 == '-')return Token(DEC);else if(ch2 == '=')return Token(ASSIGN_SUBTRACT);else{putchar(ch2);return Token(SUBTRACT);}case '*':ch2 = readChar();if(ch2 == '=')return Token(ASSIGN_MULTI);else{putchar(ch2);return Token(MULTI);}case '/':ch2 = readChar();if(ch2 == '=')return Token(ASSIGN_DIVIDE);else{putchar(ch2);return Token(DIVIDE);}case '>':ch2 = readChar();if(ch2 == '=')return Token(GE);else{putchar(ch2);return Token(GT);}case '<':ch2 = readChar();if(ch2 == '=')return Token(LE);else{putchar(ch2);return Token(LT);}case '!':ch2 = readChar();if(ch2 == '=')return Token(NE);else{putchar(ch2);return Token(NOT);}case '=':ch2 = readChar();if(ch2 == '=')return Token(EQ);else{putchar(ch2);return Token(ASSIGN);}case '&':ch2 = readChar();if(ch2 == '&')return Token(AND);else{putchar(ch2);return Token(NONE);}case '|':ch2 = readChar();if(ch2 == '|')return Token(OR);else{putchar(ch2);return Token(NONE);}case '(':return Token(PARENTHESIS_START);case ')':return Token(PARENTHESIS_END);case '{':return Token(BRACE_START);case '}':return Token(BRACE_END);case ',':return Token(COMMA);case ';':return Token(SEMICOLON);}return Token(NONE);}Token BufferedReader::readToken(){char ch = readChar();if(ch == '+' || ch == '-' || ch == '*' || ch == '/' ||\   ch == '>' || ch == '<' || ch == '=' || ch == '!' ||\   ch == '&' || ch == '|'||\   ch == '(' || ch == ')' || ch == '{' || ch == '}' ||\   ch == ',' || ch == ';'){pushChar(ch);return this->readOperator();}else if(ch >= '0' && ch <= '9'){pushChar(ch);return this->readInt();}else if(ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z' || ch == '_'){pushChar(ch);return this->readIDOrKey();}else if(ch == EOF){return Token(EOF);}else{return Token(NONE);}}Token BufferedReader::readIDOrKey(){char* p_name = new char[256];int len = 0;char ch;while(true){ch = readChar();if(ch >= 'a' && ch <= 'z' || ch >= 'A' && ch <= 'Z' || ch >= '0' && ch <= '9' || ch == '_'){p_name[len++] = ch;}else{pushChar(ch);p_name[len++] = 0;break;}}for(int i = 0; i <= 10; i++){if(strcmp(p_name, keywords[i]) == 0){delete[] p_name;return Token(i);}}return Token(ID, -1, p_name);}Token BufferedReader::readInt(){int res = 0;char ch;while(true){ch = readChar();if(ch >= '0' && ch <= '9'){res = res * 10 + ch - '0';}else{pushChar(ch);return Token(CONST, res);}}}int main(){//freopen("D:/Documents/Visual Studio 2010/Projects/proj2/Debug/in.txt", "r", stdin);BufferedReader reader = BufferedReader();while(true){Token t = reader.readToken();if(t.type == EOF)break;t.print();}return 0;}