cs.cpp

词法分析程序,输入一段代码就可以将其代码以单个的词法分析结果

#include <iostream>

#include<stdio.h>
#include<string>


using namespace std;

FILE *f; //定义一个文件变量 
static int line = 1; //表示光标所在的行数 
struct ID{ char *name; int count;}id[100];//用于存放ID号码
static int I = 0; //用于记录ID存放的数量 
int Number[100]; //用于存放数字 
static int P = 0; //用于记录存放数字的个数 
int error[100] = {0}; //用于记录错误所在的行数
static int K = 0; //记录错误次数 
void Error(); //记录错误
void loginID(char *); //注册ID号 
void loginNumber(int &); //记录数字 
void noteLine(char &); //记录光标所在的行数 
void print(); //输出分析结果
int same(char *chr); //判断单词是否已经存在


void Error() 
{ error[K++] = line; }

/*
void loginID(char *chr)
{
int i = 0;
while( i < I && !strcmp(chr,id[i].name) )//检测是否已经注册 
{
i++;
id[i].count++;
} 
i = I++; 
id[i].name = chr; //新的ID注册
id[i].count++;
} 

*/
/*
void loginID(char *chr)
{
if( same(chr) ) //单词不存在，就注册新的ID号
id[I++].count++; 
} 

int same(char *chr)
{
for(int i = 0; i < I; i++)
if( !strcmp(chr,id[i].name) ) //单词已经存在 
{id[i].count++; //该ID号的count+1 
return 0;}
return 1; 
} 
*/ 

void loginID(char *chr) //注册ID号 
{
int k = 0;
int h = 0;
for(int i = 0; i < I; i++)
{
if(!strcmp(chr,id[i].name)) //如果单词已经存在 
{
id[i].count++; 
k = 1;
}
}
//这一段一直有错误 ！ 
if(k == 0) //该单词不存在 
{ 
h = I + 1; 
//I = h; 
id[h].count++;
id[h].name = chr; 
//strcpy(id[h].name ,chr);
}

} 


void loginNumber(int ν) 
{ Number[P++] = nu; }

void noteLine(char &ch)
{
if ( ch == '\n' )
++line;
} 

void print()//////////////////////////输出部分 
{
//cout << "关键字以及变量:" << endl;
//for(int i = 0; i < 100; i++)
//cout << i <<" " << id[i].name << " " << id[i].count << endl;
cout << "数字：" << endl;
for(int i = 1; i <= P; i++)
cout << i << ": " << Number[i-1] << endl;
if(error[0] != 0)
{
cout << "出现的错误！" << endl;
for(int i = 1; i <= K; i++)
cout << "第" << i << "个错误： " << "第" << error[i-1] << "行" << endl; 
} 
else cout << "没有错误！" << endl; 
}

//////////////////////////////文件处理部分 
void noblank( char &ch) //跳过空格，回车 
{
noteLine(ch);
while(ch == ' ' || ch == '\n')
ch = fgetc(f);
}

void identifier(char name[],char &ch)//字母变量 
{

int i;
for(i = 0; i < 20; i++)
name[i] = '\0';
i = 0; 
while (('0'<= ch && ch <= '9')||('a'<= ch&&ch <= 'z')||('A'<= ch&&ch <='Z'))
{
name[i] = ch;
i++;
ch = fgetc(f);
}
loginID(name);
//for(int j = 0; j < i; j++)
//{cout << name[j];}
// cout << ' ';

}

int number(char &ch)//数字 
{
int num=0;
while('0'<= ch && ch <= '9')
{
num = num* 10 + (ch-'0');
ch = fgetc(f);
}
if( ('a'<= ch&&ch <= 'z')||('A'<= ch&&ch <='Z'))
{
Error();
}
else if( ch == '.') 
{;}
loginNumber(num); //记录数字 
return num; 
}

void test(char &ch)//符号 
{
char str[2]={'0/'};
if(ch == '*')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '.')
{ str[0] = ch; ch = fgetc(f);}
if(ch == ',')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '"')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '/')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '%')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '^')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '-')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '{')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '}')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '[')
{ str[0] = ch; ch = fgetc(f);}
if(ch == ']')
{ str[0] = ch; ch = fgetc(f);}
if(ch == ';')
{str[0] = ch; ch = fgetc(f);}
if(ch == ':')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '?')
{ str[0] = ch; ch = fgetc(f);}
if(ch == '(')
{ str[0] = ch; ch = fgetc(f);}
if(ch == ')')
{str[0] = ch; ch = fgetc(f);}
if(ch =='+')
{

str[0] = ch;
if((ch = fgetc(f)) == '+' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

//cout << str[0]<< endl;
} 
if(ch == '-')
{ 

str[0] = ch;
if((ch = fgetc(f)) == '-' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

//cout << str[0]<< endl;
} 
if(ch == '&')
{

str[0] = ch;
if((ch = fgetc(f)) == '&' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

//cout << str[0]<< endl;
} 
if(ch == '|')
{

str[0] = ch;
if((ch = fgetc(f)) == '|' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

//cout << str[0]<< endl;
} 
if(ch == '!')
{

str[0] = ch;
if((ch = fgetc(f)) == '=' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

//cout << str[0]<< endl;
} 
if(ch == '=')
{

str[0] = ch;
if((ch = fgetc(f)) == '=' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

} 
if(ch == '>')
{

str[0] = ch;
if((ch = fgetc(f)) == '=' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}
else 
if(ch == '>' )
{
str[1] = ch;
ch = fgetc(f);
//cout << str[0] << str[1] << endl;
}

}
if(ch == '<')
{
str[0] = ch;
if((ch = fgetc(f)) == '=' )
{
str[1] = ch;
ch = fgetc(f);
}
else 
if(ch == '<' )
{
str[1] = ch;
ch = fgetc(f);
}

}

} 

int main()
{
char ch;
char name[30];
for(int i = 0; i < 30; i++)
name[i] = '/0';
f = fopen("c.txt","r"); //打开指定输入文件 
if (f == NULL)
cout<<"文件不存在！"<
ch = fgetc(f);
while(!feof(f)) 
{
noblank( ch ); //跳过回车，空格 
if( ( ch >= 'a' && ch <= 'z' )||( ch >= 'A' && ch <= 'Z' ))
{ identifier(name,ch); } //处理字母 
else if( ch >= '0'&& ch <= '9')
{ number(ch); } //处理数字 
else
{ test(ch); } //处理符号 
}
print(); //打印词法分析结果 
fclose(f); //关闭文件 
system("pause");
return 0;
}