compiler/词法分析/lexer.cpp

#include<iostream>
#include<stdio.h>
#include<string.h>
#include<conio.h>
#include<windows.h>
#include"gets.h"

#define MAX 4000

using namespace std;

enum
{
    UNDERLINE = 0,//下划线
    LETTER = 1,//字母
    NUMBER = 2,//数字
    SYMBOL = 3,//符号
    SYMBOLERROR = 4,//错误符号
    IDENTIFIERERROR = 5//错误标识符
};

char data[MAX];
char letter[MAX];

bool isfloat = false;//浮点数判断
bool isbool = false;//布尔判断
bool notes = false;//注释判断
bool isvariable = false;//标识符判断
bool isiderror = false;//错误标识符判断

//关键字及其对应种别码与助记符
string key[32]={"char","double","enum","float","int","long","short","signed",
                "struct","union","unsigned","void","for","do","while","break","continue",
                "if","else","goto","switch","case","default","return","auto","extern","register",
                "static","const","sizeof","typedef","volatile"};
int keyNum[32]={1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32};
string keyword[32]={"CHAR","DOUBLE","ENUM","FLOAT","INT","LONG","SHORT","SIGNED",
                "STRUCT","UNION","UNSIGNED","VOID","FOR","DO","WHILE","BREAK","CONTINUE",
                "IF","ELSE","GOTO","SWITCH","CASE","DEFAULT","RETURN","AUTO","EXTERN","REGISTER",
                "STATIC","CONST","SIZEOF","TYPEDEF","VOLATILE"};

//符号的种别码与助记符
string symbol[33]={"+","-","*","/","%","++","--",">","<","==",
                    "!=",">=","<=","&&","||","!","=","+=","-=",
                    "*=","/=","%=",",","(",")","[","]","{","}",
                    ";","/*","*/","'"};
int symbolNum[33]={33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,66};
string symbolword[33]={"PLUS","MINUS","MULTI","RDIV","MODULO","INC","DEC","GT","LT","EQ","NEQ",
	                    "GE","LE","AND","OR","NOT","ASSIGN","PLUS_A","MINUS_A","MUL_A","DIV_A",
                        "MOD_A","COMMA","LR_BRAC","RR_BRAC","LS_BRAC","RS_BRAC","L_PRA","R_PRA",
                        "SEMIC","L_ANNO","R_ANNO","QMARK"};

int num;
int length;

void Getword();//处理data里的各类字符
void error(FILE *fp,int type,string word);

string identify(char s,int n);//返回标识符
string Number(char s,int n);//返回数字
string symbolstr(char s,int n);//返回符号
string variable(char s,int n);//返回标识符

string Keyword(int n);//根据关键词种别返回关键词
string Symbolword(int n);//根据符号种别返回符号

bool isNum(char s);//判断是否是数字
bool isLetter(char s);//判断是否是字母
bool issymbol(char s);//判断是否是符号
bool isBool(string s);//因为表里没有bool关键字 但有布尔类型 所以额外加了一个判断
 
int wordtype(char str);//字符类型判断
int iskeyword(string s);//返回关键词种别码
int isSymbol(string s);//返回符号种别码

int main()
{
    char filename[MAX] = "input.txt";//根据输入文件名修改
    getfdstr(filename,data);//预处理，去除输入文件中的空格，存在data里
    length = strlen(data);
    Getword();
    getch();
}

void Getword()
{
    FILE *fp;
    int key = 0;
    int count = 0;

    fp = fopen("output.txt", "w");
    if (fp == NULL)
    {
        printf("Error: Couldn't open output file\n");
        system("pause");
        exit(0);
    }
    for(num = 0; num < length;)
    {
        char str;
        string word;
        str = data[num];
        key = wordtype(str);
        switch(key)
        {
            case UNDERLINE:
                word = variable(str,num);
                printf("%s  (%s,70)   标识符\n",word.c_str(),word.c_str());
                fprintf(fp,"%s  (%s,70)   标识符\n",word.c_str(),word.c_str());
                isvariable = false;
                break;
            
            case LETTER:
                word = identify(str,num);
                if(notes) break;
                else if (isvariable)
                {
                    if(iskeyword(word))
                    {
                        printf("%s  (%s,%d)   关键字\n",word.c_str(),Keyword(iskeyword(word)).c_str(),iskeyword(word));
                        fprintf(fp,"%s  (%s,%d)   关键字\n",word.c_str(),Keyword(iskeyword(word)).c_str(),iskeyword(word));
                    }
                    else
                    {
                        printf("%s  (IDE,70)   标识符\n",word.c_str());
                        fprintf(fp,"%s  (IDE,70)   标识符\n",word.c_str());
                    }
                    break;
                }
                else
                {
                    if(!word.compare("bool"))
                    {
                        printf("%s  (BOOL,%d)   关键字\n",word.c_str(),67);
                        fprintf(fp,"%s (BOOL,%d)   关键字\n",word.c_str(),67);
                    }
                    else if(isbool)
                    {
                        printf("%s  (CONDST_BOOL,%d)   布尔型\n",word.c_str(),67);
                        fprintf(fp,"%s  (CONDST_BOOL,%d)   布尔型\n",word.c_str(),67);
                        isbool = false;
                    }
                    else
                    {
                        printf("%s  (%s,70)   标识符\n",word.c_str(),word.c_str());
                        fprintf(fp,"%s  (%s,70)   标识符\n",word.c_str(),word.c_str());
                        isvariable = false;
                    }
                    break;
                }
            
            case NUMBER:
                word = Number(str,num);
                if(notes) break;
                else if(isiderror)
                {
                    error(fp,IDENTIFIERERROR,word);
                    break;
                }
                else
                {
                    if(isfloat)
                    {
                        printf("%s  (CONST_FLOAT,69)   浮点型\n",word.c_str());
                        fprintf(fp,"%s  (CONST_FLOAT,69)   浮点型\n",word.c_str());
                        isfloat = false;
                    }
                    else
                    {
                        printf("%s  (CONST_INT,68)   整型\n",word.c_str());
                        fprintf(fp,"%s (CONST_INT,68)   整型\n",word.c_str());
                    }
                    break;
                }
            case SYMBOL:
                word = symbolstr(str,num);
                if(notes)
                {
                    if(count == 0)
                    {
                        printf("%s  (%s,%d)   界限符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        fprintf(fp,"%s  (%s,%d)   界限符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        count++;
                    }
                    break;
                }
                else
                {
                    if(isSymbol(word) == SYMBOLERROR)
                    {
                        error(fp,SYMBOLERROR,word);
                        break;
                    }
                    if(!word.compare("+")||!word.compare("-")||!word.compare("*")||!word.compare("/")||!word.compare("%")||
					    !word.compare("++")||!word.compare("--")||!word.compare(">")||!word.compare("<")||!word.compare("==")||
					    !word.compare("!=")||!word.compare(">=")||!word.compare("<=")||!word.compare("&&")||!word.compare("||")||
					    !word.compare("!")||!word.compare("=")||!word.compare("+=")||!word.compare("-=")||!word.compare("*=")||
					    !word.compare("/=")||!word.compare("%="))
                    {
                        printf("%s  (%sk,%d)   运算符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        fprintf(fp,"%s  (%sk,%d)   运算符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        break;
                    }
                    if(!word.compare("*/"))
                    {
                        printf("————内容被注释————\n");
                        fprintf(fp,"————内容被注释————\n");
                        printf("%s  (%s,%d)   界限符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        fprintf(fp,"%s  (%s,%d)   界限符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        count = 0;
                        break;
                    }
                    printf("%s  (%s,%d)   界限符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        fprintf(fp,"%s  (%s,%d)   界限符\n",word.c_str(),Symbolword(isSymbol(word)).c_str(),isSymbol(word));
                        break;
                }
        }

    }
    fclose(fp);
}