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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. int myStrlen(char s[]) {
  5.     int i;
  6.     for (i = 0; s[i] != '\0'; i++);
  7.     return i;
  8. }
  9.  
  10. char *setPalindrome(char s[]) {
  11.     int i, len = myStrlen(s);
  12.  
  13.     if (len % 2 != 0) {
  14.         return NULL;
  15.     }
  16.  
  17.     char *tmp = (char *)malloc(sizeof(char) * (2 * len + 1));
  18.     if (tmp == NULL) {
  19.         return NULL;
  20.     }
  21.  
  22.     for (i = 0; i < len; i++) {
  23.         tmp[i] = s[i];
  24.     }
  25.  
  26.     for (i = 0; i < len; i++) {
  27.         tmp[len + i] = s[len - 1 - i];
  28.     }
  29.  
  30.     tmp[2 * len] = '\0';
  31.     return tmp;
  32. }
  33.  
  34. int main() {
  35.     char nyuryoku[1024];
  36.     char *kaibun;
  37.  
  38.     scanf("%s", nyuryoku);
  39.     kaibun = setPalindrome(nyuryoku);
  40.  
  41.     if (kaibun == NULL) {
  42.         printf("%s\n  -> (null)\n", nyuryoku);
  43.     } else {
  44.         printf("%s\n  -> %s\n", nyuryoku, kaibun);
  45.         free(kaibun);
  46.     }
  47.  
  48.     return 0;
  49. }
  50.  
Success #stdin #stdout 0s 5288KB
comments (?)
stdin 
abc
stdout 
abc
  -> (null)
https://ideone.com/14X6xA
language:
C (gcc 8.3)
created:
9 days ago
visibility:
public

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