词法分析（C++)
2011-05-30 02:18
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/*
*词法分析.cpp
*@author liuxiaochun
*
*/
#include<iostream>
#include<string.h>
using namespace std;
#define MaxSize 1000
char LetterProcess(char ch); //以字母开头的串处理
char NumberProcess(char ch); //以数字开头的串的处理
char OtherProcess(char ch); //其它字符串的处理
void isKeyWord(char letter[]); //判断是关键字还是标识符
char *KeyWord[65] ={"include","auto","const","double","float","int","short","struct","unsigned","enum",
"break","continue","else","for","long","signed","switch","void","case","default",
"goto","register","sizeof","typedef","volatile","char","do","extern","if","return",
"static","union","while","asm","dynamic_cast","bool","explicit","new","static_cast","typeid",
"catch","false","operator","template","typename","class","friend","private","this","using",
"const_cast", "inline","public","throw","virtual","delete","mutable","protected","true","wchar_t",
"namespace","reinterpret_cast","try","cin","cout"};
int isAlpha(char c); //字母
int isDigital(char c); //数字
int isSpace(char c); //空格
int is_char(char c); //下划线
int isNumber(char c); //判断数符串后的下一符号 若为以下则返回1用以判断该串是否为数值
FILE *f = fopen("test.cpp","r"); //打开需要扫描的源文件
int main()
{
char str[200];
int choose;
char c;
while(true)
{
cout<<"请选择需要分析的源文件：1，程序内置源文件；2，输入文件的路径"<<endl;
cin>>choose;
if(choose==2)
{
cout<<"请输入文件路径:";
scanf("%s",&str);
f=fopen(str,"r");
}
if(f==NULL)
{
cout<<"Can't open file!"<<endl;
break;
}
else
{
c =fgetc(f); //读取第一个字符
while(c!=EOF)
{
if(isAlpha(c))
c = LetterProcess(c);
else
if(isDigital(c))
c = NumberProcess(c);
else
c =OtherProcess(c);
}
}
getchar();
fclose(f);
}
return 0;
}
int isAlpha(char c) //是否字母
{
if( ('a'<= c && c<='z')||('A'<=c && c<='Z'))
return 1;
else
return 0;
}
int isDigital(char c) //是否数字
{
if('0'<=c && c<='9')
return 1;
else
return 0;
}
int isSpace(char c) //是否空格
{
if( c==' ')
return 1;
else
return 0;
}
int is_char(char c) //下划线
{
if(c=='_')
return 1;
else
return 0;
}
int isNumber(char c) //判断数符串后的下一符号 若为以下则返回1
{
switch(c)
{
case ' ':
case '>':
case ',':
case ';':
case '/':
case '*':
case '+':
case '-':
case ']':
case '<':
case '=':
case ')':
case '/n':
return 1;
default:
return 0;
}
}
char LetterProcess(char ch) //以字母开头的串处理
{
int i =-1;
char LetterTemp[MaxSize];
memset(LetterTemp, 0x00, sizeof(LetterTemp));
while(isAlpha(ch)||isDigital(ch)||is_char(ch)) //是字母、数字、下划线
{
LetterTemp[++i] = ch;
ch = fgetc(f);
}
if(ch=='.') //头文件标识符处理
{
LetterTemp[++i]=ch;
ch = fgetc(f);
if(ch=='h')
{
LetterTemp[++i]= ch;
LetterTemp[i+1]='/0';
cout<<LetterTemp<<"/t/t头文件名"<<endl;
ch = fgetc(f);
}
}
else
{
LetterTemp[i+1] = '/0';
isKeyWord(LetterTemp); //判断是关键字还是标识符
}
return ch;
}
void isKeyWord(char letter[]) //判断是否关键字
{
int mark = 0;
for(int i = 0; i<63; i++)
{
if(strcmp(letter,KeyWord[i]) == 0) //对比
{
mark = 1;
break;
}
}
if(mark==1)
cout<<letter<<"/t/t关键字"<<endl;
else
cout<<letter<<"/t/t标识符"<<endl;
}
//数值处理
char NumberProcess(char ch)
{
int i = -1;
char NumberTemp[MaxSize];
memset(NumberTemp, 0x00, sizeof(NumberTemp));
while(isDigital(ch)||ch=='.') //数符处理
{
NumberTemp[++i] = ch;
ch = fgetc(f);
}
if(isNumber(ch)==1) //检查数符串的下一位以判定该串是否表示数值
{
NumberTemp[i+1] = '/0';
cout<<NumberTemp<<"/t/t数值"<<endl;
return ch;
}
else
{
while(isSpace(ch)==0) //不是空格为字符串或者其他
{
NumberTemp[++i] = ch;
ch = fgetc(f);
}
NumberTemp[i+1] = '/0';
cout<<NumberTemp<<"/t/t非法标准符"<<endl;
}
return ch;
}
//特殊符号 注释 运算符处理
char OtherProcess(char ch) //特殊符号 空格 换行等处理
{
int i = -1;
char OtherTemp[MaxSize];
if(isSpace(ch)==1) //都是空格处理
{
while(isSpace(ch))
{
ch = fgetc(f);
}
return ch;
}
else
{
if(ch=='/n'||ch=='/t') //换行处理 制表符tab处理
{
while(ch=='/n'||ch=='/t')
{
ch = fgetc(f);
}
return ch;
}
else
{
char temp;
switch(ch)
{
//特殊符号的处理
case ',':
case ';':
case '#':
case '{':
case '}':
case '[':
case ']':
case '(':
case ')':
case ':':
case '.':
cout<<ch<<"/t/t特殊符号"<<endl;
ch = fgetc(f);
return ch;
break;
case '>':
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch == '>') //'>'与'>>'处理
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t特殊符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t特殊符号"<<endl;
return ch;
break;
case '<': //'<'与'<<'处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch == '<')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t特殊符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t特殊符号"<<endl;
return ch;
break;
//以下就运算符号与注释符号的处理
case '-': //'-'、'--'与'-='处理 ->
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='-'||ch=='='||ch=='>')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t特殊符号"<<endl;
return ch;
break;
case '+': //'-'、'--'与'-='处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='+'||ch=='=')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t运算符号"<<endl;
return ch;
break;
case '=': //'-'、'--'与'-='处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='=')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t运算符号"<<endl;
return ch;
break;
case '&': //'&'、'&&'符号处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='&')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t运算符号"<<endl;
return ch;
break;
case '*': //'-'、'--'与'-='处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='=')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t运算符号"<<endl;
return ch;
break;
case '|': //'||'运算符处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='|')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
return ch;
break;
case '!': //'!'非运算符处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='=')
{
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
}
else
cout<<temp<<"/t/t运算符号"<<endl;
return ch;
break;
case '/': //'/'、'/='运算与'/*'、'//'处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
if(ch=='='||ch=='/'||ch=='*')
{
switch(ch)
{
case '=':
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t运算符号"<<endl;
ch = fgetc(f);
break;
case '/':
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
while(ch!='/n')
{
ch = fgetc(f);
}
cout<<OtherTemp<<"/t/t注释符号(该符号所在的行后面的内容都是注释)"<<endl;
ch=fgetc(f);
break;
case '*':
OtherTemp[++i]=ch;
OtherTemp[i+1] = '/0';
ch=fgetc(f);
while(ch!='*')
{
ch = fgetc(f);
}
ch = fgetc(f);
if(ch=='/')
cout<<OtherTemp<<"/t/t注释符号('/*'与'*/'之间内容都是注释)"<<endl;
ch=fgetc(f);
break;
}
}
else
cout<<temp<<"/t/t运算符号"<<endl;
return ch;
break;
//串的处理"词法分析";
case '"': //串" "处理
memset(OtherTemp, 0x00, sizeof(OtherTemp));
i = -1;
temp = ch;
OtherTemp[++i]=ch;
ch = fgetc(f); //取下一个字符
OtherTemp[++i]=ch;
while(ch!='"')
{
ch = fgetc(f);
OtherTemp[++i]=ch;
}
OtherTemp[i+1] = '/0';
cout<<OtherTemp<<"/t/t串"<<endl;
ch = fgetc(f);
return ch;
break;
}
}
}
return ch;
}
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