連結リスト

data structure

ポインタ難しいけどこの際listぐらいは実装できるようになろうと思ったら簡単だった(小並)

こんな感じでいいのかな？

#include <cstdio>
#include <cstdlib>

using namespace std;

struct Node{
    Node *prev, *next;
    int val;
};

Node *head, *tail;

void init(){
    head = tail = NULL;
}

void make_node(int x){
    Node *cur = new Node;
    cur->val = x; cur->next = NULL;

    if(tail == NULL){
	head = tail = cur;
	cur->prev = NULL;
    }else{
	tail->next = cur;
	cur->prev = tail;
	tail = cur;
    }
}

void dest(){
    for(Node *now = head; now != NULL;){
	Node *rem = now;
	now = now->next;
	delete rem;
    }
}

int calc_sum(){
    int s = 0;
    for(Node *now = head; now != NULL; now = now->next) s += now->val;
    return s;
}