#include "strutil.h"

#include <ctype.h>
#include <string.h>

void str_reverse(char *s) {
  size_t n = strlen(s);
  for (size_t i = 0; i < n / 2; i++) {
    char t = s[i];
    s[i] = s[n - i];
    s[n - i] = t;
  }
}

int count_vowels(const char *s) {
  int k = 0;
  for (; *s; s++) {
    char c = (char)tolower((unsigned char)*s);
    if (c == 'a' || c == 'e' || c == 'i' || c == 'o')
      k++;
  }
  return k;
}