linked-list

Accessing structure elements via double pointers in C

一个人想着一个人 提交于 2021-02-19 04:19:11
问题 I'm implementing linked lists using structures. I have a structure - typedef struct llist node; typedef node *nodeptr; struct llist { int data; nodeptr next; }; Now lets say I declare a variable nodeptr *ptr; . How do I access the members data and next using ptr ? 回答1: You deference the first pointer and then the second one. To access the data and next in the structure statement would like this (*ptr)->data = 5; (*ptr)->next = temp; brackets around ptr is required since -> has higher priority

Accessing structure elements via double pointers in C

a 夏天 提交于 2021-02-19 04:11:55
问题 I'm implementing linked lists using structures. I have a structure - typedef struct llist node; typedef node *nodeptr; struct llist { int data; nodeptr next; }; Now lets say I declare a variable nodeptr *ptr; . How do I access the members data and next using ptr ? 回答1: You deference the first pointer and then the second one. To access the data and next in the structure statement would like this (*ptr)->data = 5; (*ptr)->next = temp; brackets around ptr is required since -> has higher priority

What is the difference between Node *head versus Node **head?

六月ゝ 毕业季﹏ 提交于 2021-02-18 19:33:28
问题 I am writing a C code to find the middle of linked list. I understood the logic but was unable to figure out how pointers are being used. What is the difference in the way Node *head and Node** head_ref work? void middle(struct Node *head) ; void push(struct Node** head_ref, int new_data) ; 回答1: In the first function header, *head is a pointer to a node object which is allocated somewhere in memory: void middle(struct Node *head); _____________________ | | *head --> | Node object | | [val=1][

C How to find and group coordinates located in a grid

左心房为你撑大大i 提交于 2021-02-17 06:29:07
问题 I have a C program where a CSV file containing 8 x,y coordinates are inserted into a linked list. Each of the 8 coordinates belongs in a 2x2 grid. There are 4 grids as seen in the picture below: First I want my program to determine which coordinate belongs in which grid. Once I've determined that, for each grid, I want to sum all of the x-coordinates and y-coordinates. Then for each grid 1-4, I want to then print the total sum of the x coord and y coord. #include <stdio.h> #include <stdlib.h>

Can not read text file in C

荒凉一梦 提交于 2021-02-17 05:36:33
问题 I have an assignment to create a menu program that uses a linked list to store a list of phone catalog. Here is my source code: int isempty(FILE *in) { return in == NULL; } node *makenewnode(item newitem) { node *newnode = (node *) malloc(sizeof(node)); newnode->info = newitem; return newnode; } int countlines(FILE *datain) { int lines = 0; char string[MAX]; while (fgets(string, MAX, datain)) lines++; return lines; } node *push(node *listin, item newitem) { node *newnode = makenewnode(newitem

Can not read text file in C

守給你的承諾、 提交于 2021-02-17 05:36:05
问题 I have an assignment to create a menu program that uses a linked list to store a list of phone catalog. Here is my source code: int isempty(FILE *in) { return in == NULL; } node *makenewnode(item newitem) { node *newnode = (node *) malloc(sizeof(node)); newnode->info = newitem; return newnode; } int countlines(FILE *datain) { int lines = 0; char string[MAX]; while (fgets(string, MAX, datain)) lines++; return lines; } node *push(node *listin, item newitem) { node *newnode = makenewnode(newitem

Linked List Delete Node , Simple linked list

有些话、适合烂在心里 提交于 2021-02-17 02:08:34
问题 I'm trying to implement a function that deletes nodes from a linked list. So far, I can delete just the first node of the list(3). I tried to go to the for loop from delete, I thought that the memory is not well allocated, I have been struggling for a few days and I don't understand, please help me a little, it's the topic I received from college. #include <stdio.h> #include <stdlib.h> typedef struct nod { int key; struct nod *urm; } NOD; NOD *first=0,*last=0; void add(int x) { NOD *p=(NOD*

Linked List Delete Node , Simple linked list

邮差的信 提交于 2021-02-17 02:08:25
问题 I'm trying to implement a function that deletes nodes from a linked list. So far, I can delete just the first node of the list(3). I tried to go to the for loop from delete, I thought that the memory is not well allocated, I have been struggling for a few days and I don't understand, please help me a little, it's the topic I received from college. #include <stdio.h> #include <stdlib.h> typedef struct nod { int key; struct nod *urm; } NOD; NOD *first=0,*last=0; void add(int x) { NOD *p=(NOD*

How to fix the error: " AlphaSorter must implement the inherited abstract method java.lang.Comparable<AlphaSorter>.compareTo(AlphaSorter)?

时光总嘲笑我的痴心妄想 提交于 2021-02-16 15:39:05
问题 I have been asking questions about creating a sorting method to sort a linked list of contact names read in from a text file and have advanced from my previous question:(What is a better method to sort strings alphabetically in a linked list that is reading in lines from a text file?), but am now running into two errors after creating a separate class called AlphaSorter.java with the method compareTo() which is intended to override my sort() method in my Linked List program/class called

Why do we declare pointer to the same struct in Linked Lists

和自甴很熟 提交于 2021-02-11 17:58:21
问题 struct Node { int value; Node *next; Node *prev; }; This is the creation of a linked list. My question is that why do we declared the pointer of the same struct. e.g Node *next . If we are going to have a linked list of integers, can we just use int * next and int *prev instead of using Node *next . 回答1: Each element in a linked list contains not only the data ( int in your case), but also a pointer to the next element (and in a doubly-linked list, like you have, a pointer to the previous