0

```
/*Task:
Two ordered linklist contain number. eg.1->2->3-> and 2->3->5
**Print** union of them eg.1->2->3->5 ,remove duplication, can't change
linklist
Problem : 1. append() might need to be modified.
2. dnot't know how to use append() to complete the task.
*/
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include <stdlib.h>
typedef struct lnode Lnode;
struct lnode {
int data;
Lnode *next;
};
Lnode * makeNode( int data )
{
Lnode *new_node =(Lnode *)malloc( sizeof( Lnode ));
if( new_node == NULL ) {
fprintf(stderr,"Error: memory allocation failed.\n");
exit( 1 );
}
new_node->data = data;
new_node->next = NULL;
return( new_node );
}
Lnode * get_list( void )
{
Lnode *head = NULL;
Lnode *new_node;
Lnode *index_node;
int ch;
while((ch = getchar())!='\n'){
new_node = makeNode(ch-48);
if(head == NULL){
head = new_node;
index_node = head;
}
else {
index_node->next = new_node;
index_node = index_node->next;
}
}
return( head );
}
void print(Lnode* head)
{
Lnode* p = head->next;
int t=1;
printf("print：");
do
{ printf("%d",p->data);
p=p->next;
t++;
}while(p);
}
Lnode * append( Lnode *node, Lnode *head ){
Lnode *new_node = head;
if(head == NULL){
return node;
}
if(node == NULL){
return head;
}
while(new_node->next !=NULL){
new_node = new_node->next;
}
new_node->next = node;
new_node->next->next = NULL;
return head;
}
Lnode* union_list(Lnode *list1,Lnode *list2)
{
Lnode *list3,*head;
head = list3 = (Lnode*)malloc(sizeof(Lnode));
list3->next = NULL;
while(list1 && list2){
if(list1->data < list2->data){
list1= append(list1,list3);
list1 = list1->next;
}
else if(list1->data == list2->data){
list3 = append(list1,list3);
list1 = list1->next;
list2 = list2->next;
}
else{
list3 = append(list2,list3);
list2 = list2->next;
}
}
return list3;
}
void main()
{
Lnode* head,*list1,*list2;
printf("list1：");
list1 = get_list();
printf("list2：");
list2 = get_list();
head = union_list(list1,list2);
print(head);
getchar();
}
```