#include <stdio.h>
#include <string.h>

// version 1 (array notation)
int string_length_v1(char str[]) {
  int len = 0;
  // equivalent to while (str[len] != '\0')
  while (str[len]) {
    len++;
  }
  return len;
}

// version 2 (pointer notation)
int string_length_v2(char* str) {
  int len = 0;
  while (*str) {
    len++;
    str++; // pointer arithmetic
  }
  return len;
}

// version 3 (pointers, but clever)
int string_length_v3(char* str) {
  char* p = str;
  while (*p) {
    p++;
  }
  return p - str;
}

int main() {

  char str[] = "Hello";
  size_t len = strlen(str);

  printf("String: %s\n", str);
  printf("Length: %zu\n", len);
  printf("Values: %d %d %d %d %d %d\n",
      str[0], str[1], str[2], str[3], str[4], str[5]);

  return 0;
}