- c语言单向链表的问题？？？
-
#include<stdio.h> #include<stdlib.h> struct node{ int num; struct node *next; }; //构建空的链表 struct node* InitList(struct node *L){ L = (struct node*)malloc(sizeof(struct node)); L = NULL; printf_s("InitList sucess!"); return L; } //创建单链表 struct node* CreateList(struct node *L,int n){ struct node *temp,*p; L = (struct node*)malloc(sizeof(struct node)); L->next = NULL; temp=L; for (int i = 0; i < n; i++){ p = (struct node*)malloc(sizeof(struct node)); scanf_s("%d", &p->num); temp->next = p; temp = p; } temp->next = NULL; return L; } void PrintList(struct node *L){ struct node *temp = L; while (temp != NULL){ printf_s("%d", temp->num); temp = temp->next; } } void PrintMenu(){ printf_s("------Menu------\n"); printf_s("0 InitList\n"); printf_s("1 CreateList\n"); printf_s("2 PrintList\n"); } void main(){ int n,c; struct node *La; PrintMenu(); printf_s("Enter the command: "); scanf_s("%d", &c); switch (c){ case 0: La = InitList(La); break; case 1: printf_s("Enter the number of LinkList: "); scanf_s("%d", &n); La = CreateList(La, n); break; case 2: PrintList(La); break; default: printf_s("ERROR,Enter again: "); break; } system("pause"); }为什么主函数case 0 的La = InitList(La); 这句报错： error C4700: uninitialized local variable 'La' used。 ？？？？
完善了一下，头结点没存数，print时要从第二个开始：
#include<stdio.h>
#include<stdlib.h>
struct node{
int num;
struct node *next;
};
//构建空的链表
void InitList(struct node *&L){//修改
L = (struct node*)malloc(sizeof(struct node));
L->next = NULL;
L->num=0;
printf_s("InitList sucess!");
}
//创建单链表
void CreateList(struct node *&L,int n){//修改
struct node *temp,*p;
L = (struct node*)malloc(sizeof(struct node));
L->next = NULL;
L->num=0;
temp=L;
for (int i = 0; i < n; i++){
p = (struct node*)malloc(sizeof(struct node));
scanf_s("%d", &p->num);
temp->next = p;
temp = p;
}
temp->next = NULL;
}
void PrintList(struct node *L){
struct node *temp = L->next;//修改，头结点不使用
while (temp != NULL){
printf("%d", temp->num);
temp = temp->next;
}
}
void PrintMenu(){
printf_s("------Menu------\n");
printf_s("0 InitList\n");
printf_s("1 CreateList\n");
printf_s("2 PrintList\n");
}
void main(){
int n,c;
struct node *La;
c=1;
while(c>=0)
{
PrintMenu();
printf_s("Enter the command: ");
scanf_s("%d", &c);
switch (c){
case 0:
InitList(La);
break;
case 1:
printf_s("Enter the number of LinkList: ");
scanf_s("%d", &n);
CreateList(La, n);
break;
case 2:
PrintList(La);
break;
default:
printf_s("ERROR,Enter again: ");
break;
}
}
struct node *te;//增加释放空间
if(La)
{
te=La->next;
free(La);
La=te;
}
system("pause");
}
-
- 热爱学习的呆萌的文青 运行出现错误，指向void InitList(struct node *&L)
- 4 年多之前 回复
-
- 热爱学习的呆萌的文青 不太清楚La是头指针还是头结点？
- 4 年多之前 回复
struct node *La;
->
struct node *La = (node *)malloc(sizeof(node));
-
- 热爱学习的呆萌的文青 la 这个头指针也是需要动态分配的吗？
- 4 年多之前 回复
可以用引用。给你改了一部分，自己再完善吧，还需要free
#include<stdio.h>
#include<stdlib.h>
struct node{
int num;
struct node *next;
};
//构建空的链表
void InitList(struct node *&L){//修改
L = (struct node*)malloc(sizeof(struct node));
L = NULL;
printf_s("InitList sucess!");
}
//创建单链表
void CreateList(struct node *&L,int n){//修改
struct node *temp,*p;
L = (struct node*)malloc(sizeof(struct node));
L->next = NULL;
temp=L;
for (int i = 0; i < n; i++){
p = (struct node*)malloc(sizeof(struct node));
scanf_s("%d", &p->num);
temp->next = p;
temp = p;
}
temp->next = NULL;
}
void PrintList(struct node *L){
struct node *temp = L;
while (temp != NULL){
printf_s("%d", temp->num);
temp = temp->next;
}
}
void PrintMenu(){
printf_s("------Menu------\n");
printf_s("0 InitList\n");
printf_s("1 CreateList\n");
printf_s("2 PrintList\n");
}
void main(){
int n,c;
struct node *La;
c=1;
while(c>=0)
{
PrintMenu();
printf_s("Enter the command: ");
scanf_s("%d", &c);
switch (c){
case 0:
InitList(La);//修改
break;
case 1:
printf_s("Enter the number of LinkList: ");
scanf_s("%d", &n);
CreateList(La, n);//修改
break;
case 2:
PrintList(La);
break;
default:
printf_s("ERROR,Enter again: ");
break;
}
}
system("pause");
}
