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  1. %{
  2. /* Program to recognize a C program */
  3. int COMMENT = 0;
  4. int cnt = 0;
  5. %}
  6.  
  7. /* Definitions section */
  8. identifier [a-zA-Z_][a-zA-Z0-9_]*  // Updated to allow underscores in identifiers
  9. %%
  10.  
  11. /* Preprocessor Directives */
  12. #.*                     { printf("\n%s is a PREPROCESSOR DIRECTIVE", yytext); }
  13.  
  14. /* Keywords */
  15. int|float|char|double|while|for|do|if|break|continue|void|switch|case|long|struct|const|typedef|return|else|goto
  16.                         { printf("\n\t%s is a KEYWORD", yytext); }
  17.  
  18. /* Comments */
  19. "/*"                    { COMMENT = 1; cnt++; }  // Enter comment block and increment comment counter
  20. "*/"                    { COMMENT = 0; }
  21.  
  22. /* Function Definition */
  23. {identifier}\({         { if (!COMMENT) printf("\n\nFUNCTION\n\t%s", yytext); }
  24.  
  25. /* Blocks */
  26. \{                      { if (!COMMENT) printf("\nBLOCK BEGINS"); }
  27. \}                      { if (!COMMENT) printf("\nBLOCK ENDS"); }
  28.  
  29. /* Identifiers */
  30. {identifier}(\[[0-9]*\])? { if (!COMMENT) printf("\n%s is an IDENTIFIER", yytext); }
  31.  
  32. /* String Literals (handles escape sequences) */
  33. \"([^\\\"]|\\.)*\"       { if (!COMMENT) printf("\n\t%s is a STRING", yytext); }
  34.  
  35. /* Numbers (Integers) */
  36. [0-9]+                  { if (!COMMENT) printf("\n\t%s is a NUMBER", yytext); }
  37.  
  38. /* Assignment Operator */
  39. =                       { if (!COMMENT) printf("\n\t%s is an ASSIGNMENT OPERATOR", yytext); }
  40.  
  41. /* Relational Operators */
  42. <=|>=|<|==|>            { if (!COMMENT) printf("\n\t%s is a RELATIONAL OPERATOR", yytext); }
  43.  
  44. /* Semicolon (End of Statement) */
  45. \;                      { if (!COMMENT) ECHO; printf("\n"); }
  46.  
  47. /* Catch-all for unmatched characters */
  48. .                       { if (!COMMENT) printf("\nUnmatched character: %s", yytext); }
  49.  
  50. %%
  51.  
  52. /* Main function to read the input file and start lexical analysis */
  53. int main(int argc, char **argv) {
  54.     if (argc > 1) {
  55.         FILE *file;
  56.         file = fopen(argv[1], "r");
  57.         if (!file) {
  58.             printf("Could not open %s\n", argv[1]);
  59.             exit(0);
  60.         }
  61.         yyin = file;
  62.     }
  63.     yylex();  // Start lexical analysis
  64.     printf("\n\nTotal No. of comments are %d\n", cnt);
  65.     return 0;
  66. }
  67.  
  68. /* Handle end of input */
  69. int yywrap() {
  70.     return 1;
  71. }
  72.  
Success #stdin #stdout #stderr 0.02s 6984KB
comments (?)
stdin
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#include <stdio.h>
#include <conio.h>

void main() {
    int a = 1, b = 2, c;
    c = a + b;
    printf("Sum: %d", c);
}
stdout
copy 
Standard output is empty
stderr
copy 
ERROR: /home/TynlBs/prog:3:4: Syntax error: Operator expected
ERROR: /home/TynlBs/prog:71:1: Syntax error: Unexpected end of file
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? ERROR: Can't ignore goal at this port
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ?    Exception: (3) program ? ERROR: Unknown option (h for help)
   Exception: (3) program ? EOF: exit
https://ideone.com/q9udgR
language:
Prolog (swi 7.6.4)
created:
1 day ago
visibility:
public

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