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

#define N 20
#define LEN 30

int apart_by_array(char str[][LEN], const char *s);
int apart_by_pointer(char *strp[], const char *s);

int main(void)
{
  int n1, n2, i;
  char str[N][LEN], *strp[N], *s = "This is not an apple";

  /* 配列版 */
  n1 = apart_by_array(str, s);
  printf("配列版の分解\n");
  for (i = 0; i < n1; i++)
    printf("%3d: %s\n", i + 1, str[i]);
  
  /* ポインタ版 */
  n2 = apart_by_pointer(strp, s);
  printf("ポインタ版の分解\n");
  for (i = 0; i < n2; i++) {
    printf("%3d: %s\n", i + 1, strp[i]);
    free(strp[i]);
  }
  
  return 0;
}

/* 配列版の分解 */
int apart_by_array(char str[][LEN], const char *s)
{
  int n, i, j;
  
  if (strlen(s) == 0) return 0;
  for (i = 0, n = 0; s[i]; i++)
    if (s[i] != ' ') n++;
  if (n == 0) return 0;
  
  for (i = 0; s[i] == ' '; i++);
  for (j = 0, n = 0; s[i]; i++) {
    if (s[i] != ' ')
      str[n][j++] = s[i];
    else {
      str[n][j] = '\0';
      while (s[i] == ' ') i++;
      if (s[i] == '\0' && s[i - 1] == ' ') break;
      i--;
      n++;
      j = 0;
    }
  }
  str[n][j] = '\0';
  return n + 1;
}

int apart_by_pointer(char *strp[], const char *s)
{
  int n = 0;
  char *p, *ds;
  
  ds = strdup(s);
  
  if ((p = strtok(ds, " ")) == NULL) {
    free(ds);
    return 0;
  }
  strp[n++] = strdup(p);
  while (p = strtok(NULL, " "))
    strp[n++] = strdup(p);
  free(ds);
  return n;
}

#include <stdio.h>

#define N 20
#define M 20

int main(void)
{
    char str[] = "This is not an apple";
    char word[N][M+1];
    int i = 0, j = 0, k = 0;

    while (str[i] != '\0') {
        if (str[i] != ' ') {
            word[j][k] = str[i];
            k++;
            if (k >= M) break;
        }
        else {
            word[j][k] = '\0';
            k = 0;
            j++;
            if (j >= N) break;
        }
        i++;
    }
    word[j][k] = '\0';

    return 0;
}

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

#define N 20

int main(void)
{
    char str[] = "This is not an apple";
    char *word[N];
    int i = 0, j;

    word[i] = strtok(str, " ");
    while (word[i] != NULL && i < N-1) {
        i++;
        word[i] = strtok(NULL," ");
    }

    return 0;
}