連結リスト(Linked List)

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

/* セルの定義 */
typedef struct cell{
    struct cell *next;
    int data;
}cell;

cell c1, c2, c3;

int main(void){

    cell *p;

    c1.next = &c2;
    c1.data = 23;
    c2.next = &c3;
    c2.data = 31;
    c3.next = NULL;
    c3.data = 97;

    for(p= &c1; p != NULL; p = p -> next)
       printf("%d\n", p -> data);

   return 0;
}

/*
    構造体の初期化2
*/

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

typedef struct cell{
    struct cell *next;
    int data;
}cell;

int main(void){

    cell *p;

    // 初期化の順番に注意！
    cell c3 = {NULL, 97};
    cell c2 = { &c3, 31};
    cell c1 = { &c2, 23};

    for(p= &c1; p != NULL; p = p -> next)
       printf("%d\n", p -> data);

   return 0;
}

/*
    headerの導入
*/

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

typedef struct cell{
    struct cell *next;
    int data;
}cell;

int main(void){

    cell *p;

    cell c3 = {NULL, 97};
    cell c2 = { &c3, 31};
    cell c1 = { &c2, 23};
    cell header = {&c1, };

    for(p=header.next; p != NULL; p = p -> next)
       printf("%d\n", p -> data);

   return 0;
}

23
31
97

/*
    要素の追加
*/
#include <stdio.h>
#include < stdlib.h>

typedef struct cell{
    struct cell *next;
    int data;
}cell;

int main(void){

    cell *p;
    cell *pt;

    cell c3 = {NULL, 97};
    cell c2 = { &c3, 31};
    cell c1 = { &c2, 23};
    cell header = { &c1, };

    cell ct;
    ct.data = 123;

    p = &c2;
    pt = &ct;
    pt -> next = p -> next;
    p -> next = pt;

    for(p = header.next; p != NULL; p = p -> next)
       printf("%3d\n", p -> data);

   return 0;
}

  23
  31
123
  97

123
  23
  31
  97

/*
    要素の削除
*/

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

typedef struct cell{
    struct cell *next;
    int data;
}cell;

int main(void){

    cell *p, *pt;

    cell c3 = {NULL, 97};
    cell c2 = { &c3, 31};
    cell c1 = { &c2, 23};
    cell header = { &c1, };

    pt = &c1;   // c1の次のリスト(すなわちc2)を削除

    p = pt -> next;
    pt -> next = p ->next;
    for(p = header.next; p != NULL; p = p -> next)
       printf("%3d\n", p -> data);

    return 0;
}

  23
  97

  31
  97

/*
    リストの最後のセルを削除する関数 delete_LC(struct cell *q)
*/

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

typedef struct cell{
    struct cell *next;
    char name[30];
}cell;

void delete_LC(struct cell *q){
    cell *p;
    p = q -> next;
    if(p -> next == NULL){
       q -> next = NULL;
       printf("%25s\n", p -> name);
       if(strcmp(q -> name,"And Then There Were None!") == 0)
          printf("%20s\n", q -> name);
       return;
    }
    if(p != NULL){
       delete_LC(q -> next);
    }
}

int main(void){

    int i;
    cell c10 ={NULL, "Ten Little Indians"};
    cell c9 = { &c10, "Nine Little Indians"};
    cell c8 = { &c9, "Eight Little Indians"};
    cell c7 = { &c8, "Seven Little Indians"};
    cell c6 = { &c7, "Six Little Indians"};
    cell c5 = { &c6, "Five Little Indians"};
    cell c4 = { &c5, "Four Little Indians"};
    cell c3 = { &c4, "Three Little Indians"};
    cell c2 = { &c3, "Two Little Indians"};
    cell c1 = { &c2, "One Little Indian"};
    cell header = { &c1, "And Then There Were None!"};

    for(i=0; i<10; i++){
       delete_LC(&header);
    }

    return 0;
}