單鏈表的合併還是挺簡單的，直接上程式碼吧。

#include <stdio.h>
#include <stdlib.h>
typedef int ElementType;
typedef struct Node *PtrToNode;
struct Node {
    ElementType Data;
    PtrToNode   Next;
};
typedef PtrToNode List;
List Read(); /* 連結串列讀取 */
void Print( List L ); /*連結串列輸出；空連結串列將輸出NULL */
List Merge( List
 
 L1, List L2 );  /*連結串列合併*/
int main()
{
    List L1, L2, L;
    L1 = Read();  //讀取連結串列1
    L2 = Read();  //讀取連結串列2
    L = Merge(L1, L2);  
    Print(L);
    Print(L1);
    Print(L2);
    return 0;
}
List Merge( List L1, List L2 )
{
    List L, p1, p2, r ;
    p1 = L1->Next;
    p2 = L2->Next;
    L =
 
 (List)malloc(sizeof(struct Node));
    L->Next = NULL;
    r = L;
    while (p1 && p2){
        if(p1->Data < p2->Data){
            r->Next = p1;
            r = p1;
            p1 = p1->Next;
        }
        else{
            r->Next = p2;
            r = p2;
            p2 =
 
 p2->Next;
        }
    }
    if(p1)
        r->Next = p1;
    else
        r->Next = p2;
 L1->Next = NULL;
 L2->Next = NULL;
 return L;
}
List Read()
{
    int n, i;
    List L, p, s;
    scanf("%d",&n);
    L = (List)malloc(sizeof(struct Node));
    L->Next = NULL;
    p = L;
    for(i = 0;i < n; ++i){
        s = (List)malloc(sizeof(struct Node));
        scanf("%d",&s->Data);
        s->Next = p->Next;
        p->Next = s;
        p = s;
    }
    return L;
}
void Print(List L)
{
 List p;
 p = L->Next;
 if (L->Next==NULL)
 {
  printf("NULL");
 }
 while(p)
 {
  printf("%d ", p->Data);
  p = p->Next;
 }
 printf("\n");
}