ソースコード

  1|/* array03.c */
  2|
  3|#include <stdio.h>
  4|
  5|int main(void)
  6|{
  7|  int a[4] = {1, 2, 3, 4}, i;
  8|
  9|  for (i = 0; i < 4; i++){
 10|    printf("&a[%d] = %p\n", i, &a[i]);                                                
 11|  }
 12|  printf("\na = %p\n", a);
 13|  return 0;
 14|}

実行結果

&a[0] = 0x7fff5fbff620
&a[1] = 0x7fff5fbff624
&a[2] = 0x7fff5fbff628
&a[3] = 0x7fff5fbff62c

a = 0x7fff5fbff620

a のアドレスは a[0] と同じですね。しかも a は配列の名前です。実は配列の名前は、その配列の先頭要素のアドレスを表しているのです。

  1|/* array04.c */
  2|
  3|#include <stdio.h>
  4|
  5|int main(void)
  6|{
  7|  int a[] = {10, 20, 30, 40}, i, *p;
  8|
  9|  p = a;                                                                              
 10|
 11|  for (i = 0; i < 4; i++){
 12|    printf("&a[%d] = %p, a[%d] = %d, *(p + %d) =%d\n",
 13|           i, &a[i], i, a[i], i, *(p + i));
 14|  }
 15|  return 0;
 16|}

&a[0] = 0x7fff5fbff630, a[0] = 10, *(p + 0) =10
&a[1] = 0x7fff5fbff634, a[1] = 20, *(p + 1) =20
&a[2] = 0x7fff5fbff638, a[2] = 30, *(p + 2) =30
&a[3] = 0x7fff5fbff63c, a[3] = 40, *(p + 3) =40

  1|/* array05.c */
  2|
  3|#include <stdio.h>
  4|
  5|int main(void)
  6|{
  7|  int *p, i, a[] = {20, 40 ,80, 100};
  8|
  9|  p = a;
 10|
 11|  for(i = 0; i < 4; i++){
 12|    printf("&a[%d] = %p, (p + %d) = %p, (a + %d) = %p\n",
 13|           i, &a[i], i, p + i, i, a + i);
 14|  }
 15|  return 0;                                                                           
 16|}

&a[0] = 0x7fff5fbff630, (p + 0) = 0x7fff5fbff630, (a + 0) = 0x7fff5fbff630
&a[1] = 0x7fff5fbff634, (p + 1) = 0x7fff5fbff634, (a + 1) = 0x7fff5fbff634
&a[2] = 0x7fff5fbff638, (p + 2) = 0x7fff5fbff638, (a + 2) = 0x7fff5fbff638
&a[3] = 0x7fff5fbff63c, (p + 3) = 0x7fff5fbff63c, (a + 3) = 0x7fff5fbff63c