链式物理结构4

/*
   链式物理结构练习
   */
#include <stdio.h>
#include <stdlib.h>
typedef struct node {
int num;
    struct node *p_next;
} node;
static node head, tail;
int main() {
    int num = 0;
node *p_node = NULL;
head.p_next = &tail;
//按顺序把用户提供的整数插入到链中
do {
printf("请输入一个数字：");
scanf("%d", &num);
if (num >= 0) {
            node *p_tmp = (node *)malloc(sizeof(node));
if (p_tmp) {
p_tmp->num = num;
p_tmp->p_next = NULL;
for (p_node = &head;p_node != &tail;p_node = p_node->p_next) {
node *p_first = p_node;
node *p_mid = p_first->p_next;
node *p_last = p_mid->p_next;
if (p_mid == &tail || p_mid->num > num) {
p_first->p_next = p_tmp;
p_tmp->p_next = p_mid;
break;
}
}
}
}
else {
break;
}
} while (1);
//打印链中所有数字
for (p_node = &head;p_node != &tail;p_node = p_node->p_next) {
node *p_first = p_node;
node *p_mid = p_first->p_next;
node *p_last = p_mid->p_next;
if (p_mid != &tail) {
printf("%d ", p_mid->num);
}
}
printf("\n");
//释放所有动态分配节点
while (head.p_next != &tail) {
node *p_first = &head;
node *p_mid = p_first->p_next;
node *p_last = p_mid->p_next;
        p_first->p_next = p_last;
free(p_mid);
p_mid = NULL;
}
return 0;
}