can i have a sample of a working lexical analyzer??plss...i need it for my project..
paulo_war -1 Newbie Poster
Freaky_Chris 299 Master Poster
Hmm...show us some work? Lets see how far you get.
Let us know where you get stuck.
Read up on Lexical Analyzers...http://en.wikipedia.org/wiki/Lexical_analysis
paulo_war -1 Newbie Poster
i have a lexical analyzer here.. but i dont know how to put loops in it..can you help me?
paulo_war -1 Newbie Poster
/*************************************************************************
HEADRER FILES
*************************************************************************/
#include <iostream.h>
#include<conio.h>
#include <stdlib.h>
#include <stdio.h>
#include <ctype.h>
#include<string.h>
/*************************************************************************
GLOBAL DECLARARIONS FOR THE
HOLE CODE REPRESENT EACH TOKEN
CASE
*************************************************************************/
const int M_Dec=4,E_E=5,N_F_C=6;
const int CS=7,DEC=1,IF=2,SWITCH=3;
const int UK=0,N_F=1,N_F_B=2,N_F_N=3;
/*************************************************************************
USED CLASSES IN THE CODE FOR
THE COMPILER PART SIMULATION
*************************************************************************/
class ddr
{
public:
char* token;
int type;
ddr* next;
};
class Double
{
public:
char* token3;//Exists code
char* token;//for good code
char* token2;//for bad code
int type;
Double* next3;
Double* next;//for good code
Double* next2;//for bad code
};
class analayzer
{
public:
char* f_n;
char stack[10];
int stack_no;
Double* rs_head;
ddr* df_head;
Double* cd_head;
Double* thras;
analayzer(int);
void tok_s();
void create_tokens();
void add_code(char*);
int token_not_added(char*);
void compile();
int dd_detect(char*);
int dec_detect(char*);
int if_dect(char*);
int swch_dect(char*);
int lo_dect(char*);
int dig_dect(char*);
int mult_dect(char*);
void push();
void pop();
void ddrine(char*);
void error(int);
void print();
void print_tokens();
}/*************************************************************************
MAIN CLASS FUNCTION DEFINITION
*************************************************************************/
analayzer::analayzer(int x)
{
char* f_n;
if(x==2)f_n="code1.cpp";
else f_n="code2.cpp";
this->f_n = new char[strlen(f_n)];
strcpy(this->f_n,f_n);
rs_head=NULL;
tok_s();
df_head = NULL;
cd_head = NULL;
thras = NULL;
stack_no=-1;
create_tokens();
compile();
print_tokens();
}
Double* p;
void analayzer::tok_s()
{
// this will made a link list of the defined code
rs_head=new Double;//asign a pointer from the type Double to it
rs_head->token3=new char[4];//the char * token 3 to a new char
strcpy( rs_head->token3, "int" );//give token3 int word
rs_head->token3[3]='\0';//then close end it by /0
rs_head->type=DEC;//the int part to 1
rs_head->next3=new Double;//continue the link list
p=rs_head->next3;
p->token3=new char[6];
strcpy(p->token3,"float");
p->token3[5]='\0';
p->type=DEC;
p->next3=new Double;
p=p->next3;
p->token3=new char[5];
strcpy(p->token3,"long");
p->token3[4]='\0';
p->type=DEC;
p->next3=new Double;
p=p->next3;
p->token3=new char[7];
strcpy(p->token3,"double");
p->token3[6]='\0';
p->type=DEC;
p->next3=new Double;
p=p->next3;
p->token3=new char[6];
strcpy(p->token3,"short");
p->token3[5]='\0';
p->type=DEC;
p->next3=new Double;
p=p->next3;
p->token3=new char[5];
strcpy(p->token3,"byte");
p->token3[4]='\0';
p->type=DEC;
p->next3=new Double;
p=p->next3;
p->token3=new char[3];
strcpy(p->token3,"if");
p->token3[2]='\0';
p->type=IF;
p->next3=new Double;
p=p->next3;
p->token3=new char[5];
strcpy(p->token3,"else");
p->token3[4]='\0';
p->next3=new Double;
p=p->next3;
p->token3=new char[7];
strcpy(p->token3,"switch");
p->token3[6]='\0';
p->type=SWITCH;
p->next3=new Double;
p=p->next3;
p->token3=new char[5];
strcpy(p->token3,"case");
p->token3[4]='\0';/////*************************
p->next3=new Double;
p=p->next3;
p->token3=new char[8];
strcpy(p->token3,"ddrault");
p->token3[7]='\0';
p->next3=NULL;
}
void analayzer::create_tokens()
{
FILE* file;
char ch;
char* token;
int i=0;
file = fopen(f_n,"r");
if (file == NULL)
{
cout<<"Error:an error occured while reading from file\n";
getch();
exit(EXIT_FAILURE);
}
fseek(file,0,SEEK_SET);
while((ch = fgetc(file)) !=EOF)
{
if (ch == ' ' || ch == '\n')
{
if (i!=0)
token[i]='\0';
if(token_not_added(token))
add_code(token);
i=0;
}
else
if(ch>32&&ch<48 || ch>57&&ch<65 || ch>90&&ch<95 || ch>122&&ch<127)
{
if (i!=0)
token[i]='\0';
if (token_not_added(token))
add_code(token);
token = new char[10];
token[0] = ch;
token[1] = '\0';
i=0;
if(token_not_added(token))
add_code(token);
}
else
{
if(i==0)
token = new char[10];
token[i] = ch;
i++;
}
}
}
void analayzer::add_code(char* token)
{
Double* p;
p = cd_head;
if (cd_head == NULL)
{
cd_head = new Double;
cd_head->token = new char[strlen(token)];
strcpy(cd_head->token,token);
cd_head->next = NULL;
}
else
{
while(p->next!=NULL)
p= p->next;
p->next = new Double;
p = p->next;
p->token = new char[strlen(token)];
strcpy(p->token,token);
p->next = NULL;
}
}
int analayzer::token_not_added(char* token)
{
Double* p;
p=cd_head;
while(p->next!= NULL)
p=p->next;
if (strcmp(p->token,token)==0)
return 0;
return 1;
}
void analayzer::compile()
{
Double* p;
p=cd_head;
int state = 0;
int if_stmt=0;
int flag=1;
while(flag)
{
switch(state)
{
case 0:if(dec_detect(p->token))
state = 1;
else
if (dd_detect(p->token))
{
state=3;
if_stmt=0;
}
else
if(if_dect(p->token))
state=6;
else
if(swch_dect(p->token))
state=8;
else
if(strcmp(p->token,"{")==0)
{
state=0;
push();
}
else
if(strcmp(p->token,"}")==0)
{
pop();
state=0;
}
else
if(strncmp(p->token,"case",4)==0)
state=10;
else
if(strcmp(p->token,"break")==0)
state=5;
else
if(strcmp(p->token,"else")==0)
state=0;
else
{
error(UK);
}
break;
case 1:if(dd_detect(p->token))
error(M_Dec);
else
ddrine(p->token);
state = 2;
break;
case 2:if(strcmp(p->token,",")==0)
state=1;
else
if(strcmp(p->token,";")==0)
{
state=0;
}
else
{
error(N_F);
state=0;
}
break;
case 3:if (strcmp(p->token,"=")==0)
state=4;
else
{
error(E_E);
state=0;
}
break;
case 4:if(dig_dect(p->token) || dd_detect(p->token))
{
if(if_stmt)
state=7;
else
state=5;
}
else
{
error(UK);
}
break;
case 5:if(mult_dect(p->token))
{
state=4;
if_stmt=0;
}
else
if(strcmp(p->token,";")==0)
state=0;
else
{
error(N_F);
state=0;
}
break;
case 6:if(strcmp(p->token,"(")==0)
{
state=4;
if_stmt=1;
}
else
{
error(N_F_B);
state=0;
}
break;
case 7:if(lo_dect(p->token))
{
state=4;
}
else
{
if(strcmp(p->token,")")==0)
{
state=0;
}
else
{error(N_F_B);
state=0;}}
break;
case 8:if(strcmp(p->token,"(")==0)
state=9;
else
{
error(N_F_B);
state=0;
}
break;
case 9:if(dd_detect(p->token))
state=7;
else
{
error(UK);
state=0;
}
break;
case 10:if(dig_dect(p->token))
state=11;
else
{
error(N_F_N);
state=11;
}
break;
case 11:if(strcmp(p->token,":")==0)
state=0;
else
{
error(N_F_C);
state=0;
}
break;
}
p=p->next;
if (p ==NULL)
flag=0;
}
if (stack_no>-1)
{pop();error(CS);}
}
int analayzer::dd_detect(char* token)
{
ddr* p;
p=df_head;
while(p!=NULL)
{
if (strcmp(p->token,token)==0)
return 1;
p=p->next;
}
return 0;
}
int analayzer::dec_detect(char* token)
{
Double* p;
p=rs_head;
while(p!=NULL)
{
if(strcmp(p->token3,token)==0 && p->type == DEC)
return 1;
p=p->next3;
}
return 0;
}
int analayzer::if_dect(char* token)
{
/*Double* p;
p=rs_head;
while(p!= NULL)
{*/
if(strcmp(token,"if")==0)
return 1;
/*p=p->next;
}*/
return 0;
}
int analayzer::swch_dect(char* token)
{
if(strncmp(token,"switch",6)==0)
return 1;
return 0;
}
int analayzer::mult_dect(char* token)
{
if (strcmp(token,"*")==0||strcmp(token,"+")==0||strcmp(token,"/")==0||strcmp(token,"-")==0)
return 1;
return 0;
}
void analayzer::push()
{
stack_no++;
stack[stack_no]='{';
}
void analayzer::pop()
{
if(stack_no>=0)
stack[stack_no]='\0';
// else
stack_no--;
}
int analayzer::dig_dect(char* token)
{
for (int i=0;i<strlen(token);i++)
if(!isdigit(token[i]))
return 0;
return 1;
}
int analayzer::lo_dect(char* token)
{
if (strcmp(token,">")==0||strcmp(token,"<")==0||strcmp(token,"=")==0)
return 1;
return 0;
}
void analayzer::ddrine(char* token)
{
ddr* p;
if(df_head ==NULL)
{
df_head = new ddr;
df_head->token= new char[strlen(token)];
strcpy(df_head->token,token);
df_head->next=NULL;
}
else
{
p=df_head;
while(p->next!=NULL)
p=p->next;
p->next = new ddr;
p=p->next;
p->token=new char[strlen(token)];
strcpy(p->token,token);
p->next=NULL;
}
}
void analayzer::error(int type)
{
char* ErrStr;
Double* p;
ErrStr=new char[30];
switch (type)
{
case UK:
ErrStr="\nSyntax Error:\tundefined variable";
break;
case N_F:
ErrStr="\nSyntax Error:\texpecting;";
break;
case N_F_B:
ErrStr="\nSyntax Error:\tExpecting (,),{,}";
break;
case N_F_N:
ErrStr="\nSyntax Error:\tExpecting Value";
break;
case M_Dec:
ErrStr="\nSyntax Error:\tMultiple Declaration";
break;
case E_E:
ErrStr="\nSyntax Error:\tExpecting =";
break;
case N_F_C:
ErrStr="\nSyntax Error:\tExpecting | :";
break;
case CS:
ErrStr="\nSyntax Error:\tEach { should have }:";
break;
}
if(thras==NULL)
{
thras = new Double;
thras->token2=new char[strlen(ErrStr)];
strcpy(thras->token2,ErrStr);
thras->next2=NULL;
}
else
{
p=thras;
while(p->next2!=NULL)
p=p->next2;
p->next2=new Double;
p=p->next2;
p->token2 = new char[strlen(ErrStr)];
strcpy(p->token2,ErrStr);
p->next2=NULL;
}
}
void analayzer::print()
{
Double* p;
p=thras;
if(thras==NULL)
cout<<"\nRESULT: success\n";
else
while(p!=NULL)
{
cout<<p->token2;
p=p->next2;
}
getch();
}
void analayzer::print_tokens()
{
Double* p;
p=cd_head;
int x;
cout<<"\nTokens are\n";
while(p!=NULL)
{
x++;
if(x<4)
cout<<p->token<<"\t\t";
else {
cout<<"\n\n";
x=0;
}
p=p->next;
}
}
FILE* new_file(char*);
FILE* open_file(char*);
int write_code_to_file(char*);
void main()
{
clrscr();
analayzer* comp;
int x;
char* f_n;
FILE* file;
while(1){
cout<<"1.Good Code\n2.Bad Code\n";
cin>>x;
if(x==2){
comp = new analayzer(2);
comp->print();
exit(1);
}
if(x==1){
comp = new analayzer(1);
comp->print();
exit(1);
}
else exit(1);
}
}
FILE* new_file(char* name)
{
FILE* file;
file = fopen(name,"w");
fclose(file);
return file;
}
FILE* open_file(char* f_n)
{
FILE* file;
file = fopen(f_n,"r");
fclose(file);
return file;
}
int write_code_to_file(char* f_n)
{
int row=4;
char c;
FILE* file;
file=fopen(f_n,"a+");
if (file == NULL)
return 0;
gotoxy(5,row);
c=getchar();
while (c!='~')
{
fputc(c,file);
gotoxy(wherex(),row);
c=getchar();
if (c=='\n')
{
row+=1;
gotoxy(5,row);
}
}
fclose(file);
return 1;
} William Hemsworth commented: Learn to post.. -1
VernonDozier 2,218 Posting Expert Featured Poster
Code tags, formatting, and ask a specific question. Your question is way too vague and there's way too much code, even with formatting and tags, to go through without some guidance.
[code=cplusplus] // paste code here
[/code]
paulo_war -1 Newbie Poster
what should i do now?...
paulo_war -1 Newbie Poster
what should i do with this "
// paste code here"?
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