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YACC Program to evaluate the arithmetic expression and check validation and print the result

arithmetic.l


//lex program

/* declaration section in this sections we will decleared the different value and include the header file which we are using in this program to run this program */

%{
#include<stdio.h>
#include "y.tab.h"
extern int yylval;
%}

/* this sections is known as defined section in which we defined the rule and regulation of regular expression which will be going to accept or not */

%%
[0-9]+ {
          yylval=atoi(yytext);
          return NUMBER;
       }
[\t] ;
[\n] return 0;
. return yytext[0];
%%

int yywrap()
{
return 1;
}


arithmatic.y

/* yacc program for soving arithmatic expression */

/* decleration section in this sections we will decleared the different  value and include the header file which we are using in this program to run this program */

%{
    #include<stdio.h>
    int flag=0;
    
%}



%token NUMBER

%left '+' '-' 
%left  '*' '/' '%'
%left '(' ')'

/* this sections is known as defined section in which we defined the rule and regulation of regular expression which will going to accept or not */

%%
ArithmeticExpression: E{
         printf("\nResult=%d\n",$$);
         return 0;
        }
E:E'+'E {$$=$1+$3;}
 |E'-'E {$$=$1-$3;}
 |E'*'E {$$=$1*$3;}
 |E'/'E {$$=$1/$3;}
 |E'%'E {$$=$1%$3;}
 |'('E')' {$$=$2;}
 | NUMBER {$$=$1;}
;

%%

void main()
{ 
   printf("\nEnter Any Arithmetic Expression which can have operations Addition, Subtraction, Multiplication, Divison, Modulus and Round brackets:\n");
   yyparse();
  if(flag==0)
   printf("\nEntered arithmetic expression is Valid\n\n");
  
}

void yyerror()
{
   printf("\nEntered arithmetic expression is Invalid\n\n");
   flag=1;
}



how to run

                save the file as above  name
               compile flex file "flex arithmetic.l"
               compile yacc file " yacc -d arithmetic.y"
               compile c file generated by  flex and yacc "cc lex.yy.c  y.tab.c  -o  arithmetic -ll "
               run the obj file  "./arithmetic"
              
                                    



               


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