Lexical analyzer Code in C Language

Implement Lexical Analyzer code for subset of C using C Language.

#include  
 #include  
 #include  
 #include  
 #define max 100  
 typedef struct lit_tab  
 {  
   char token[max];  
 }littab;  
 typedef struct iden_tab  
 {  
   char token[max];  
 }identab;  
 typedef struct ust  
 {  
   char token[max];  
   char type;  
   int pos;  
 }ustx;  
 littab lit_tab[50];  
 identab iden_tab[50];  
 ustx ust[100];  
 int ust_ptr=0;  
 char terminal[max][max]={"{","}","(",")","<",">","<=",">=","=",",",";","\"","+","-","*","/","void","printf","int","float","if","else"};  
 void print_ust()  
 {  
   printf("UST\n");  
   int i=0;  
   printf("TOKEN\tTYPE\tPOS\n");  
   while(i<ust_ptr) <br="">   {  
     printf("%s\t%c\t%d\n",ust[i].token,ust[i].type,ust[i].pos);  
     i++;  
     getch();  
   }  
 }  
 void print_ter()  
 {  
   printf("Literal Table");  
   int i=0;  
   clrscr();  
   while(strcmp(terminal[i],NULL)!=0)  
   {  
     printf("%d.%s\n",i+1,terminal[i]);  
     i++;  
   }  
   getch();  
 }  
 void print_lit()  
 {  
   printf("\nLiteral Table");  
   int i=0;  
   clrscr();  
   while(strcmp(lit_tab[i].token,NULL)!=0)  
   {  
     printf("%d.%s\n",i+1,lit_tab[i].token);  
     i++;  
   }  
   getch();  
 }  
 void print_iden()  
 {  
   printf("\nIdentifier Table");  
   int i=0;  
   clrscr();  
   while(strcmp(iden_tab[i].token,NULL)!=0)  
   {  
     printf("%d.%s\n",i+1,iden_tab[i].token);  
     i++;  
   }  
   getch();  
 }  
 int search_lit(char str[])  
 {  
   int i=0;  
    while(strcmp(lit_tab[i].token,NULL)!=0)  
    {  
     if(strcmp(lit_tab[i].token,str)==0)  
       return i;  
     i++;  
    }  
    return -1;  
 }  
 int insert_lit(char str[])  
 {  
   int i=0;  
   while(strcmp(lit_tab[i].token,NULL)!=0)  
   {  
     i++;  
   }  
   strcpy(lit_tab[i].token,str);  
   return i;  
 }  
 int search_iden(char str[])  
 {  
   int i=0;  
    while(strcmp(iden_tab[i].token,NULL)!=0)  
    {  
     if(strcmp(iden_tab[i].token,str)==0)  
       return i;  
     i++;  
    }  
    return -1;  
 }  
 int insert_iden(char str[])  
 {  
   int i=0;  
   while(strcmp(iden_tab[i].token,NULL)!=0)  
   {  
     i++;  
   }  
   strcpy(iden_tab[i].token,str);  
   return i;  
 }  
 int search(char str[])  
 {  
   int i=0;  
   while(strcmp(terminal[i],NULL)!=0)  
   {  
     if(strcmp(terminal[i],str)==0 )  
       return i;  
     i++;  
   }  
   return -1;  
 }  
 void ust_insert(char token[],char type,int pos)  
 {  
   strcpy(ust[ust_ptr].token,token);  
   ust[ust_ptr].type=type;  
   ust[ust_ptr].pos=pos;  
   ust_ptr++;  
 }  
 void main()  
 {  
   FILE *fp;  
   clrscr();  
   fp=fopen("lex.txt","r");  
   if(fp==NULL)  
   {  
     printf("File Not Found");  
     return;  
   }  
   char str[max],token[max];  
   int i,j;  
   while( !feof(fp) )  
   {  
     fgets(str,max,fp);  
     i=0;  
     strcpy(token,NULL);  
     while(str[i]!='\n' && str[i]!=NULL)  
     {  
       while(str[i]==' ' || str[i]=='\t')  
         i++;  
       j=0;  
       if(str[i]=='/')  
       {  
         if(str[i+1]=='/')  
         {  
           fgets(str,max,fp);  
           continue;  
         }  
         else if(str[i+1]=='*')  
         {  
           i+=2;  
           while(str[i]!='*' && str[i+1]!='/')  
           {  
             if(str[i]=='\n')  
             {  
               fgets(str,max,fp);  
               i=0;  
             }  
             i++;  
           }  
           i+=2;  
         }  
       }  
       while(str[i]!=' ' && str[i]!='\t' && str[i]!='\n')  
       {  
         if(str[i-1]=='"' && str[i]!=')')  
         {  
           while(str[i]!='"')  
           {  
             token[j]=str[i];  
             j++;i++;  
           }  
           break;  
         }  
         token[j]=str[i];  
         j++;  
         i++;  
         if(ispunct(str[i]))  
             //if(str[i]=='(' || str[i]==')' ||str[i]==';' ||str[i]==','||str[i]=='+'||str[i]=='='||str[i]=='-'||str[i]=='/'||str[i]=='*')  
           break;  
         if(ispunct(str[i-1]) )  
             //if(str[i-1]==','||str[i-1]=='='||str[i-1]=='/'||str[i-1]=='+'||str[i-1]=='-'||str[i-1]=='*')  
           break;  
       }  
       token[j]=NULL;  
       int x;  
       int l=strlen(token);  
       int pos;  
       x=search(token);  
       if(x!=-1)  
         ust_insert(token,'T',x);  
       else if(str[i-l-1]!='"' && !(token[0]>='0'&& token[0]<='9')&&strcmp(token,NULL)!=0 )  
       {  
         x=search_iden(token);  
         if(x==-1)  
         {  
           pos=insert_iden(token);  
           ust_insert(token,'I',pos);  
         }  
         else  
           ust_insert(token,'I',x);  
       }  
       else if( strcmp(token,NULL)!=0)  
       {  
         x=search_lit(token);  
         if(x==-1)  
         {  
           pos=insert_lit(token);  
           ust_insert(token,'L',pos);  
         }  
         else  
           ust_insert(token,'L',x);  
       }  
     }  
   }  
   print_ter();  
   print_lit();  
   print_iden();  
   print_ust();  
   getch();  
 }