C语言语法笔记 – 高级用法 指针数组 指针的指针 二维数组指针 结构体指针 链表 | IT宅.com

定义：类型名 *数组名[数组长度]；

char *suit[3] = {"first","second","third"};

char **p;
p = suit;

#include<stdio.h>
void main(){
int a[5] = {1,3,5,7,9};
int *num[5],i;
int **p;
for(i=0;i<5;i++){
num[i] = &a[i];
}
p = num;
for(i=0;i<5;i++){
printf("%d",**p);
p++;
}
printf("\n");
}

#include<stdio.h>
void main(){
int a[3][4] = {1,2,3,4,5,6,7,8,9,10,11,12}
int *p;
for(p = a[0]; p<a[0]+12; p++){
if((p-a[0])%4 == 0)
printf("\n");
printf("%4d",*p);
}
}

函数类型 * 函数名([形式参数类型声明表])
{
函数体
}

int (*FunctionPointer)(int a);
FunctionPointer = func;   //func为函数名
(*FunctionPointer)(100);

void main(int argc, char *argv[]){
函数体
}

struct student *p;
struct student stu;
p = &stu;
//获取子元素的三种方法：
stu.name;
(*p).name;
p->name;  //指针的方法

newptr = malloc(sizeof(struct node));

#include<stdio.h>
#define NULL 0
#define LEN sizeof(struct student)  /*定义节点的长度*/
#define NODE struct student
struct student
{
char no[5];
float score;
struct student *next;
};
struct student *create(void);
void printlist(struct student *head);
NODE * insert(NODE *head, NODE *new, int i);
NODE * dellist(NODE *head,char no[]);
void main(){
struct student *a;
struct student test1={"abc",1.0,NULL};
struct student *test2;
a = create();
printf("insert new node\n");
test2 = &test1;
a = insert(a,test2,2);
printlist(a);
printf("delete node\n");
a = dellist(a,"2");
printlist(a);
getch();
}
/*创建一个具有头结点的单链表，返回单链表的头指针*/
struct student *create(void){
struct student *head = NULL, *new1, *tail;
int count = 0;
for(;;)
{
new1 = (struct student *)malloc(LEN);  /*申请一个新结点的空间*/
printf("Input the number of student No.%d(5bytes): ",count + 1);
scanf("%5s",new1->no);
if(strcmp(new1->no, "*") == 0)   /*这里不用加取址符号，因为no就表示数组的首地址*/
{
free(new1);   /*释放最后申请的结点空间*/
break;  /*结束for语句*/
}
printf("Input the score of the student No.%d: ",count + 1);
scanf("%f",&new1->score);
count++;
/*将新结点插入到链表尾，并设置新的尾指针*/
if(count == 1){
head = new1;   /*是第一个结点，置头指针*/
} else
tail->next = new1;  /*不是第一个结点，将新结点插入到链表尾*/
tail = new1;    /*设置新的尾结点*/
}
/*置新结点的指针域为空*/
new1->next = NULL;
return(head);
}
/*输出链表*/
void printlist(struct student *head){
struct student *p;
p = head;
if(head == NULL) {
printf("List is empty!!!\n");
} else {
while(p!=NULL){
printf("%5s %4.1f\n", p->no,p->score);
p = p->next;
}
}
}
/*插入链表结点*/
NODE * insert(NODE *head, NODE *new, int i){
NODE *pointer;
/*将新结点插入到链表中*/
if(head == NULL){
head = new; new->next = NULL;
} else {
if(i == 0){
new -> next = head;
head = new;
} else {
pointer = head;
/*查找单链表的第i个结点（pointer指向它）*/
for(;pointer != NULL && i > 1; pointer = pointer->next,i--);
if(pointer == NULL)
printf("Out of the range,can't insert new node!\n");
else {  /*一般情况下pointer指向第i个结点*/
new -> next = pointer->next;
pointer->next = new;
}
}
}
return(head);
}
/*删除链表*/
NODE * dellist(NODE *head,char no[]){
NODE *front;    /*front表示要删除结点的前一个结点*/
NODE *cursor;   /*cursor表示当前要删除的结点*/
if(head == NULL) {  /*空链表*/
printf("\nList is empty\n");
return(head);
}
if(strcmp(head->no,no == 0)){  /*要删除的结点是表头结点*/
front = head;
head = head->next;
free(front);
} else {  /*非表头结点*/
front = head;
cursor = head->next;
/*通过循环移动到要删除的结点的位置*/
while(cursor != NULL && strcmp(cursor->no,no) != 0) {
front = cursor;
cursor = cursor ->next;
}
if(cursor != NULL){   /*找到需要删除的结点进行删除操作*/
front->next = cursor->next;
free(front);
} else {
printf("%5s has not been found!",*no);
}
}
return(head);
}