总结了一些指针易出错的常见问题（五）

//结构体定义
typedef  struct _person{
char* firstname;
char* lastname;
char* title;
unsigned int age;
}Person;
Person person;
//分配内存
Person *ptrPerson;
ptrPerson = (Person*) malloc (sizeof(Person));

#include<stdio.h>

int main()
{
typedef struct _alternatePerson{
char* firstname;
char* lastname;
char* title;
short age;
}AlternatePerson;;

//AlternatePerson otherperson;
AlternatePerson people[30];
typedef struct _Person{
char* firstname;
char* lastname;
char* title;
unsigned int age;
}Person;
Person person;

printf("%d\n",sizeof(Person));
printf("%d\n",sizeof(people));
return 0;

}

/*写一函数建立一个有3名学生数据的单向动态链表*/
#include<stdio.h>
#include<malloc.h>
//#define NULL 0
#define LEN sizeof(struct student)

struct student
{
long num;
float score;
struct student *next;
};
int n;
struct student *creat(void)
{
struct student *head;
struct student *p1,*p2;
n=0;
p1=p2=(struct student*)malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);
head=NULL;
while(p1->num!=0)
{
n=n+1;
if(n==1) head=p1;
else
p2->next=p1;
p2=p1;
p1=(struct student*)malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);
}
p2->next=NULL;
return(head);
}

void print(struct student *head)
{
struct student *p;
printf("\n Now,These %d record are:\n",n);
p=head;
if(head!=NULL)
do
{
printf("%ld %5.1f\n",p->num,p->score);
p=p->next;
}while(p!=NULL);
}

struct student *del(struct student *head,long num)
{
struct student *p1,*p2;
if(head==NULL) {printf("\nlist is NULL.\n"); return head; }
p1=head;
while(num!=p1->num&&p1->next!=NULL)
{
p2=p1;p1=p1->next;
}
if(num==p1->num)
{
if(p1==head) head=p1->next;
else p2->next=p1->next;
printf("delete:%ld\n",num);
n=n-1;
}
else printf("%ld not have been found: \n",num);
return (head);
}

/* insert */
struct student *insert(struct student *head,struct student *stud)
{
struct student *p0,*p1,*p2;
p1=head;
p0=stud;
if(head==NULL) { head=p0;p0->next=NULL;}
else
{
while((p0->num>p1->num)&&(p1->next!=NULL))
{
p2=p1;
p1=p1->next;
}
if(p0->num<=p1->num){
if(head==p1) head=p0;
else p2->next=p0;
p0->next=p1;
}
else
{
p1->next=p0;p0->next=NULL;
}
}
n=n+1;
return(head);
}
int main()
{
struct student *head,stu;
long del_num;
printf("input records: \n");
head=creat();
print(head);
printf("\n input the deleted number:");
scanf("%ld",&del_num);
head=del(head,del_num);
print(head);
printf("\n input the inserted record:");
scanf("%ld,%f",&stu.num,&stu.score);
head=insert(head,&stu);
print(head);
}