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  1. %{
  2.   #include<stdio.h>
  3.   #include<stdlib.h>
  4.   int result=0;
  5.   int curr=0;
  6.   char op='+';
  7.   void apply_operation();
  8. %}
  9. %option noyywrap
  10. digit [0-9]+
  11. space [ \t]
  12. %%
  13. {space};
  14. {digit}+ {
  15.         curr=atoi(yytext);
  16.         apply_operation();
  17.         }
  18. "+" {op='+';}
  19. "-" {op='-';}
  20. "*" {op='*';}
  21. "/" {op='/';}
  22. \n {
  23.   printf("Result:%d",result);
  24.   result=0;
  25.   curr=0;
  26.   op='+';
  27. }
  28. . {printf("Invalid character\n");
  29.   exit(1);
  30. }
  31. %%
  32. void apply_operation(){
  33.   switch(op){
  34.     case '+': result+=curr;break;
  35.     case '-': result-=curr;break;
  36.     case '*':result*=curr;break;
  37.     case '/':{
  38.       if(curr==0){
  39.         printf("Error division by 0\n");
  40.         exit(1);
  41.       }
  42.       result/=curr;break;
  43.     }
  44.  
  45.   }
  46. }
  47. int main(){
  48.   printf("Enter expression: ");
  49.   yylex();
  50.   return 0;
  51. }
Success #stdin #stdout #stderr 0.02s 7004KB
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stdin
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Standard input is empty
stdout
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Standard output is empty
stderr
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ERROR: /home/2Ci9jL/prog:2:3: Syntax error: Operator expected
ERROR: /home/2Ci9jL/prog:51:0: Syntax error: Unexpected end of file
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit
https://ideone.com/lGcz0D
language:
Prolog (swi 7.6.4)
created:
4 days ago
visibility:
public

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