/* definition section*/ %{  #include<stdio.h>  #include<stdlib.h>  #include<math.h>  //#define YYSTYPE double  void yyerror(char *s);  float x = 0; %} 
 
// creating tokens whose values are given by lex %token ZERO ONE POINT 
 
// following a grammer rule which is converting binary number to decimal number (float value) %% 
 
L: X POINT Y  {printf("%f",$1+x);}  | X  {printf("%d", $$);} X: X B  {$$=$1*2+$2;}  | B  {$$=$1;} Y: B Y  {x=$1*0.5+x*0.5;}   |   {;} B:ZERO   {$$=$1;}  |ONE   {$$=$1;}; 
 
%% // main function int main() {  printf("Enter the binary number : ");  // calling yyparse function which execute grammer rules and lex  while(yyparse());  printf("\n"); } // if any error  void yyerror(char *s) {  fprintf(stdout,"\n%s",s); } 
 
 
 
 
 
 
 
 
2 
 
 
/* definitions */ %{  // including required header files  #include<stdio.h>         #include<stdlib.h>  #include"y.tab.h"  // declaring a external variable yylval  extern int yylval; %} 
 
/* rules  if 0 is matched ,make yylval to 0 and return ZERO which is variable in Yacc program  if 1 is matched ,make yylval to 1 and return ONE which is variable in Yacc program  if . is matched ,return POINT which is variable in Yacc program  if line change , return 0  otherwise ,ignore*/ %% 
 
0  {yylval=0;return ZERO;}   1  {yylval=1;return ONE;}    "."  {return POINT;}   [ \t] {;} \n return 0; 
 
%% 
 
 

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