我必须将一个新的工作人员添加到工人列表中，但我必须按字母顺序将其放在正确的位置。
我为新名称提供了几个选项：
- 列表是空的，所以我只是将新名称放在列表中
- 列表中有 1 个工作人员
- 新名称<现有名称>
- 新名称比前面的名称大，但比下一个名称小
- 比姓氏大的新名称
我哪里做错了？
//first function-add a new worker to the list//
Worker * addWorker(Worker *head, char name[], char *city, int id, float
salary)
{
Worker *new = (Worker *)malloc(sizeof(Worker));
strcpy(new->name, name);
new->city = city;
new->id = id;
new->salary = salary;
if (head == NULL) //checks if the list is empty//
{
new->next = NULL;
head = new;
return head;
}
if (length(head) == 1) //checks if the list has 1 person only //
{
if (head->name < new->name)
{
head->next = new;
new->next = NULL;
return head;
}
if (head->name > new->name)
{
new->next = head;
return new;
}
}
Worker *x = head;
Worker *y = head->next;
while (x != NULL)
{
if (x->name > new->name) //checks if the name needs to be first in
the list//
{
new->next = x;
return new;
}
if ((x->name < new->name) && (y->name > new->name)) // checks if the
name needs to be somewhere in the middle of the list//
{
x->next = new;
new->next = y;
return head;
}
if ((x->name < new->name) && (y==NULL)) //checks if the name needs to
be last in the list//
{
x->next = new;
new->next = NULL;
return head;
}
x = x->next;
y = y->next;
}
return head;
}
抱歉，您的代码太复杂了，我宁愿不尝试理解它
如果 addWorker 返回新的 worker (而不是列表的新 head(，则第一个参数必须是记忆 head 的位置，因此Worker ** head .之后，您只需将列表迭代到正确的位置即可插入新工作人员。
要比较字符串，请使用 strcmp
解决方案是：
//first function-add a new worker to the list//
Worker * addWorker(Worker ** head, char name[], char *city, int id, float salary)
{
Worker * new = malloc(sizeof(Worker));
strcpy(new->name, name); /* hope the name is not too long to be saved in Worker */
new->city = city; /* hope the city is always a valid string */
new->id = id;
new->salary = salary;
while ((*head) && (strcmp(name, (*head)->name) > 0))
head = &(*head)->next;
new->next = *head;
*head = new;
return new;
}
请注意，对城市和名称没有相同的行为很奇怪，但我尊重这一点。
如果我有一些定义来拥有一个完整的程序，包括打印和删除：
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
typedef struct Worker {
char name[10];
const char * city;
int id;
float salary;
struct Worker * next;
} Worker;
//first function-add a new worker to the list//
Worker * addWorker(Worker ** head, char name[], char *city, int id, float salary)
{
Worker * new = (Worker *)malloc(sizeof(Worker));
strcpy(new->name, name); /* hope the name is not too long to be saved in Worker */
new->city = city; /* hope the city is always a valid string */
new->id = id;
new->salary = salary;
while ((*head) && (strcmp(name, (*head)->name) > 0))
head = &(*head)->next;
new->next = *head;
*head = new;
return new;
}
void pr(Worker * l)
{
while (l != NULL) {
printf("%s %s %d %fn", l->name, l->city, l->id, l->salary);
l = l->next;
}
}
void del(Worker * l)
{
while (l != NULL) {
Worker * w = l;
l = l->next;
free(w);
}
}
int main()
{
Worker * l = NULL;
addWorker(&l, "aze", "c1", 1, 1);
addWorker(&l, "qsd", "c2", 2, 2);
addWorker(&l, "aaa", "c3", 3, 3);
addWorker(&l, "wxc", "c4", 4, 4);
pr(l);
del(l);
}
编译和执行：
pi@raspberrypi:/tmp $ gcc -g -pedantic -Wextra -Wall w.c
pi@raspberrypi:/tmp $ ./a.out
aaa c3 3 3.000000
aze c1 1 1.000000
qsd c2 2 2.000000
wxc c4 4 4.000000
瓦尔格林德的处决：
pi@raspberrypi:/tmp $ valgrind ./a.out
==17053== Memcheck, a memory error detector
==17053== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==17053== Using Valgrind-3.13.0 and LibVEX; rerun with -h for copyright info
==17053== Command: ./a.out
==17053==
aaa c3 3 3.000000
aze c1 1 1.000000
qsd c2 2 2.000000
wxc c4 4 4.000000
==17053==
==17053== HEAP SUMMARY:
==17053== in use at exit: 0 bytes in 0 blocks
==17053== total heap usage: 5 allocs, 5 frees, 1,136 bytes allocated
==17053==
==17053== All heap blocks were freed -- no leaks are possible
==17053==
==17053== For counts of detected and suppressed errors, rerun with: -v
==17053== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 6 from 3)
第二个建议，如果addWorker 返回列表的新负责人而不是新的工作线程，addWorker 和 main 的新定义
Worker * addWorker(Worker * head, char name[], char *city, int id, float salary)
{
Worker ** phead = &head;
Worker * new = (Worker *)malloc(sizeof(Worker));
strcpy(new->name, name); /* hope the name is not too long to be saved in Worker */
new->city = city; /* hope the city is always a valid string */
new->id = id;
new->salary = salary;
while ((*phead) && (strcmp(name, (*phead)->name) > 0))
phead = &(*phead)->next;
new->next = *phead;
*phead = new;
return (new->next == head) ? new : head;
}
int main()
{
Worker * l = NULL;
l = addWorker(l, "aze", "c1", 1, 1);
l = addWorker(l, "qsd", "c2", 2, 2);
l = addWorker(l, "aaa", "c3", 3, 3);
l = addWorker(l, "wxc", "c4", 4, 4);
pr(l);
del(l);
}