要去看埃菲尔铁塔的顶
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/*
代码如下 ， 排版不好，建议复制到
https://web.chacuo.net/formatcpp
格式化一下查看
参考
https://blog.sina.com.cn/s/blog_68b606350100v7hf.html
实现，在此感谢原作者。
*/
#include <iostream>
#include <iostream>
#include<math.h>
#include<string>
#include<stdlib.h>
#include<stdio.h>
#include<fstream>
using namespace std;
/*
0 ~ 33 是 key区
33 是变量
34 int型
35 实型
36 char
*/
string key[34]={"main",
"auto","short","int","long","float","double","char","struct"
,"union","enum","typedef","const","unsigned","signed","extern","register"
,"static","volatile","void","if","else","switch","case","for"
,"do","while","goto","continue","break","default","sizeof","return"};
string symbol[26]={
"=","+","-","*","/","++","--","+=","-=",
"*=","/=","==","!=",">","<",">=","<=","(",
")","[","]","{","}",",",":",";" };
string text;//代码
string token; // 工作区字符串
int pText;//游标
char ch;//字符
int line;
void getChar()//读取一个字符
{
ch = text[pText++];
}
void passSpace()//忽略读取到的空格
{
while(text[pText] == ' ')
getChar();
}
int findkey( )//比对key
{
for(int i =0; i< 33 ; i ++)
{
if ( key[i] == token )
{
return i;//
}
}
return -1;
}
int findsymbol()//比对 符号
{
for(int i =0; i< 25 ; i ++)
{
if ( symbol[i] == token )
{
return i + 37 ;
}
}
return -1;
}
void Concat()// 将ch 连接到 工作区中
{
token += ch;
}
void Retract()//回退
{
ch = ' ';
pText -- ;
}
bool IsDigital()//判断是否是数字
{
return '0'<=ch && ch <='9' ? true : false;
}
bool IsLetter()// 是字母？
{
return ('a'<=ch && ch <= 'z' ) || ('A' <= ch && ch <= 'Z') ? true : false;
}
// 分析程序
void Analysis()
{
//标示符
// + - * / =
//其他符号
int code ;
token = "";//工作字符串
passSpace();
getChar();
if( IsLetter() )
{
while( IsLetter() || IsDigital() || ch == '_')
{
Concat();
getChar();
}
Retract(); //清空当前状态
code = findkey();
if(code != -1)
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
else
cout<< "(" <<33<<", "<<token<<", "<<line<< ")"<<endl;
}
else if( IsDigital())
{
while( IsDigital() )//整数识别
{
Concat();
getChar();
}
if(ch != '.')
{
Retract(); //清空当前状态
cout<< "(" <<34<<", "<<token<<", "<<line<< ")"<<endl;
}
else if( ch == '.')
{
do
{
Concat();
getChar();
}while(IsDigital() );
Retract();
cout<< "(" <<35<<", "<<token<<", "<<line<< ")"<<endl;
}
}
else if(ch==39) //识别字符常量
{
Concat();
getChar();
while(ch!=39)
{
Concat();
getChar();
}
// Retract(); 这里游标不能后退，如果后退的话 pText指向的依然还是 ' 会出现错误
cout<< "(" <<36<<", "<<token<<", "<<line<< ")"<<endl;
}
else if(ch == '=') // = , ==
{
int code ;
Concat();
getChar();
if( ch == '=')
{
Concat();
}
Retract();
code = findsymbol();
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
}
else if(ch == '+') // + += ++
{
int code ;
Concat();
getChar();
if( ch == '+' || ch == '=')
{
Concat();
}
Retract();
code = findsymbol();
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
}
else if(ch == '-') // - -= --
{
int code ;
Concat();
getChar();
if( ch == '-' || ch == '=')
{
Concat();
}
Retract();
code = findsymbol();
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
}
else if(ch == '*') // * *= */
{
int code ;
Concat();
getChar();
if( ch == '=' || ch == '/')
{
Concat();
}
Retract();
code = findsymbol();
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
}
else if(ch == '/') // / ，/= // /*
{
int code ;
Concat();
getChar();
if( ch == '=')
{
Concat();
}
Retract();
code = findsymbol();
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
}
else if (ch == '\n') line ++ ;
else
{
Concat();
int code = findsymbol();
if( code!= -1)
cout<< "(" <<code<<", "<<token<<", "<<line<< ")"<<endl;
}
}
void init(string file)
{
fstream data;
text.clear();
char ch;
data.open(file.c_str());
while(!data.eof())
{
data.get(ch);
text += ch;
}
data.close();
}
int main(int argc, char** argv)
{
init("d:/data.txt");
line = 0;
cout<<text<<endl;
while(pText < text.length())
{
Analysis();
}
return 0;
}