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  1. %{
  2. #include <stdio.h>
  3. #include <string.h>
  4. #include <ctype.h>
  5.  
  6. char str[256];
  7. %}
  8.  
  9. %%
  10.  
  11. [a-zA-Z]+   { strcpy(str, yytext); }
  12.  
  13. \n          {
  14.                 int i = 0;
  15.                 int j = strlen(str) - 1;
  16.                 int is_palindrome = 1;
  17.  
  18.                 while (i < j) {
  19.                     if (tolower(str[i]) != tolower(str[j])) {
  20.                         is_palindrome = 0;
  21.                         break;
  22.                     }
  23.                     i++;
  24.                     j--;
  25.                 }
  26.  
  27.                 if (is_palindrome)
  28.                     printf("\"%s\" IS a palindrome.\n", str);
  29.                 else
  30.                     printf("\"%s\" is NOT a palindrome.\n", str);
  31.             }
  32.  
  33. .           { /* ignore other characters */ }
  34.  
  35. %%
  36.  
  37. int main(void) {
  38.     printf("Enter a string: ");
  39.     yylex();
  40.     return 0;
  41. }
  42.  
  43. int yywrap(void) {
  44.     return 1;
  45. }
Success #stdin #stdout #stderr 0.02s 6768KB
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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/NGbYtX/prog:2:1: Syntax error: Operator expected
ERROR: /home/NGbYtX/prog:45:0: Syntax error: Unexpected end of file
ERROR: '$runtoplevel'/0: Undefined procedure: program/0
   Exception: (3) program ? EOF: exit
https://ideone.com/7ljqeI
language:
Prolog (swi 7.6.4)
created:
11 hours ago
visibility:
public

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