Aim:
Write down program to simulate the lexical analyzer which generate symbol table
according to user input.
# include <stdio.h>
# include <conio.h>
# include <string.h>
# include <stdlib.h>
void main()
{
char
str[100],str1[100],idn[100];
int i,k,flag,con[100],j,p;
clrscr();
printf("\n\n=============LEXICAL
ANALYZER================\n\n");
printf("\n\nEnter the
string::");
gets(str);
printf("\n\n---------------SYMBOLE
TABLE------------------\n\n");
printf("\n\t|| LEXEME ||
TYPE ||\n\n");
i=0;
while(str[i]!=' ')
{
str1[i]=str[i];
i++;
}
str1[i]='\0';
flag=strcmp(str1,"int");
if(flag==0)
{
printf("\n\n\t|| int keyword ||");
}
else
{
flag=strcmp(str1,"char");
if(flag==0)
{
printf("\n\n\t||
char keyword ||");
}
else
{
flag=strcmp(str1,"float");
if(flag==0)
{
printf("\n\n\t||
float keyword ||");
}
else
{
i=-1;
}
}
}
NEXT: i++;
k=0;
if(str[i]=='1'||str[i]=='2'||str[i]=='3'||str[i]=='4'||str[i]=='5')
{
printf("\n\ninvalid
identifier start with %c",str[i]);
goto END;
}
if(str[i]=='6'||str[i]=='7'||str[i]=='8'||str[i]=='9'||str[i]=='0'||str [i]=='_')
{
printf("\n\ninvalid
identifier start with %c",str[i]);
goto END;
}
while(str[i]!=',' && str[i]!=';'
&& str[i]!='=')
{
idn[k]=str[i];
i++;
k++;
}
idn[k]='\0';
printf("\n\n\n\t|| %s
identifier ||", idn);
if(str[i]=='=')
{
printf("\n\n\n\t|| =
operator ||");
i++;
while(str[i]!=',' && str[i]!=';')
{
printf("\n\n\t|| %c
",str[i]);
i++;
}
printf(" constant ||");
}
if(str[i]!=';')
{
printf("\n\n\n\t|| ,
operator ||");
goto NEXT;
}
printf("\n\n\n\t|| ;
operator ||");
printf("\n\n---------------------------------------------\n\n");
END: getch();
}
