链表

链表实现输入点集，插入新点，删除点

#include <stdio.h>
#include <malloc.h> 
 
typedef struct POINT {
	int row;
	int col;
	struct POINT *next;
}POINT;

typedef unsigned char boolean;

#define TRUE   1
#define FALSE  0

void inputPoint(POINT *hp);
void printPointList(POINT head);
void printOnePoint(POINT point);
void destoryPointLink(POINT *hp); 
void insertPoint(POINT *hp); 
POINT *searchPrePoint(POINT head, POINT thePoint);
boolean removePoint(POINT *hp);
void sortPointByRow(POINT head);

void sortPointByRow(POINT head) {
	POINT *p;
	POINT *q;
	POINT tmp;
	POINT *temp;
	
	for (p = head.next; p; p = p->next) {
		for (q = p->next; q; q = q->next) {
			if (p->row > q->row) {
				tmp = *p;
				*p = *q;
				*q = tmp;
				
				temp = p->next;
				p->next = q->next;
				q->next = temp;
			}
		}
	} 
}

boolean removePoint(POINT *hp){
	int row;
	int col;
	POINT point;
	POINT *pre;
	POINT *p;
	printf("请输入要删除的点坐标:");
	scanf("%d%d",&row,&col);
	point.row = row;
	point.col = col;
	
	pre = searchPrePoint(*hp, point);
	if (NULL != pre && NULL == pre->next) {
		return FALSE;
	} 
	if (NULL == pre) {
		pre = hp;
	}
		p = pre->next;
		pre->next = p->next;
		free(p);
	
	return TRUE;
}	
	/*
	1.若返回值为NULL，表明指定点是第一个有效节点 
	2.若返回值不为NULL，但其所指向的节点是末节点，则表明指定点不存在 
	3.其他情况，指定点存在，且不是第一个有效节点 
	*/ 
POINT *searchPrePoint(POINT head, POINT thePoint){
	POINT *p;
	POINT *q = NULL;
	
	for (p = head.next; p && (p->row != thePoint.row
	|| p->col != thePoint.col); p = p->next ){
	q = p;	
	}
	return q;//当循环结束，返回值为末节点首地址。 
}	
	
void insertPoint(POINT *hp){
	POINT *p;
	int row;
	int col;
	POINT thePoint;
	POINT *pre;
//1.输入新点坐标	
	printf("请输入新点坐标：");
	scanf("%d%d",&row,&col);
 	p = (POINT *)malloc(sizeof(POINT));
	p->row = row;
 	p->col = col;
 	p->next = NULL;

//2.输入位置点坐标
	printf("请输入要插入的位置点坐标（左插入），若想实现新节点追加到链表末尾，则，可以给一个不存在的点：");
	scanf("%d%d",&row,&col); 
	thePoint.row = row;
	thePoint.col = col;
	
//3.找到指定位置点的前驱节点	
 	pre = searchPrePoint(*hp, thePoint);
	 
//4.结果有三种情况：
//优化过
	if(NULL == pre){
		pre = hp;
	} 
	p->next = pre->next; 
	pre->next = p;
}
	/*if(NULL == pre){
		//指定点是第一个节点，应该把新点插入到第一个节点的前面，应该更改头结点链域的指向
		p->next = hp->next;
		hp->next = p;
	} else if(NULL == pre.next) {
		//指定点不存在，按约定，应该把新点追加到整个链表末尾
		p->next = pre->next;
		pre->next = p; 
	} else {
		//指定点是一个非第一个节点的任意节点； 
		p->next = pre->next; 
		pre->next = p;
	}*/
 
	
void destoryPointLink(POINT *hp) {//从左向右释放 
	POINT *p;
	
	while (hp && hp->next){
		p = hp->next;
		hp->next = p->next;
		free(p);
	}
}	
	
void printOnePoint(POINT point){
	printf("(%d,%d)", point.row, point.col);
}

void printPointList(POINT head){
	POINT *p;
	
	printf("点坐标如下：\n");
	for (p = head.next; p; p = p->next){
		printf(p == head.next ? " " : ",");
		printOnePoint(*p);
	}
	printf("\n");
}

void inputPoint(POINT *hp) {
	int row;
   	int col;
	POINT *tail;
	POINT *p;
	POINT *q; 
	
	printf("请输入一个点（任意行列值为0，结束输入）：");
	scanf("%d%d", &row, &col);
	while (row && col){
		p = (POINT *) malloc(sizeof(POINT));  
		p->row = row;
 		p->col = col;
		p->next = NULL;

		if (NULL == hp->next){
		hp->next = p; 
		} 
		else{
			tail->next = p;
		}
		tail = p;
	    printf("请输入一个点（任意行列值为0，结束输入）：");
		scanf("%d%d", &row, &col);		 
	} 
}
 
int main () {
	POINT head1 = {0};
	POINT head2 = {0}; 
	boolean ok; 
	
	inputPoint(&head1);
	printPointList(head1);
	
	insertPoint(&head1);
	printPointList(head1);
		
	sortPointByRow(head1);
	printPointList(head1);
	
	ok = removePoint(&head1);
	if (ok) {
	printPointList(head1);
	} else {
	printf("删除失败，要删除的点不存在\n");
	}
	destoryPointLink(&head1); 
}
 /*void inputPoint(POINT *hp) {
	int row;
	int col;
	
	printf("请输入一个点（任意行列值为0，结束输入）：");
	scanf("%d%d", &row, &col);
	while (row && col){
		//处理所输入的点坐标
	printf("请输入一个点（任意行列值为0，结束输入）：");
	scanf("%d%d", &row, &col);		 
	} 
}*/
   
   
   
   
/*
void inputPoint(POINT *hp) {
	int row;
	int col;
	POINT *p;
	POINT *q; 
	
	printf("请输入一个点（任意行列值为0，结束输入）：");
	scanf("%d%d", &row, &col);
	while (row && col){
		// 申请存储空间 
		p = (POINT *) malloc(sizeof(POINT)); 
 		//初始化存储空间的值，
		//并且应该生成一个“末节点” ;
        //以便未来追加到链表末尾 
		p->row = row;
 		p->col = col;
		p->next = NULL;
		//将p所指向的新节点，追加到链表的末尾 
		if (NULL == hp->next){
		hp->next = p; 
		} else{
			//先定位到末节点
			for(q = hp->next; q && q->next; q = q->next){
				//更改末节点链域的值，使之指向新节点
				q->next = p; 
			} 
		}
	    printf("请输入一个点（任意行列值为0，结束输入）：");
		scanf("%d%d", &row, &col);		 
	} 
}
*/