text: #include <malloc.h>
  
  int strlen(char *str)
  {
      int n = 0;
      while (str[n++] != '\0')
      {
      }
      return n;
  }
  
  void delchar(char *str, char c)
  {
      char *tmp = (char *)malloc(sizeof(char) * 1000);
      char *head = tmp;
      for (int i = 0; i < strlen(str); i++)
      {
          if (str[i] != c)
              *tmp++ = str[i];
      }
      int i = 0;
      for (; i < strlen(head); i++)
      {
          str[i] = head[i];
      }
      str[i] = '\0';
      free(tmp);
      free(head);
  }