C语言实现链表基本操作（交换第i个和第j个节点）Sakura丶Tears的博客-

当i或者j为1时，需要让链表的表头指向j。

代码为

/*i和j为1时情况比较特殊，需要让表头重新指向交换后的那个节点*/ if (i == 1) {          t1 = *L; for (m = 1; temp->Next != NULL; m++, temp = temp->Next) { if (m + 1 == j) { *L = temp->Next;                 t2 = temp->Next->Next;                 temp->Next->Next = t1->Next;                 t1->Next = t2;                 temp->Next = t1; } } } 

当i和j都不为1时。
节点相邻与不相邻也是不一样的。
不相邻的情况下就是让i前面的节点指向j，然后让j前面的节点指向i。如果两个节点相邻（假设i < j）j前面的节点就是i，j前面的节点指向i就是指向了自己，所以要分开写。
不相邻节点时：




代码为：

if ((i - j) != 1 && (j- i) != 1) {//非相邻结点之间交换 for (m = 1; temp->Next != NULL; m++, temp = temp->Next) { if (m + 1 == i) {                     t1 = temp; } if (m + 1 == j) {                     t2 = temp; } }             t5 = t1->Next->Next;             t3 = t1->Next;             t4 = t2->Next;             t1->Next = t4;             t2->Next = t3;             t3->Next = t4->Next;             t4->Next = t5; } 

最后一种情况，两个节点相邻：




代码为：

for (m = 1; temp != NULL; m++, temp = temp->Next) { if (m + 1 == i) {                     t1 = temp; } if (m == j) {                     t2 = temp; } }             temp = t2->Next;             t3 = t1->Next;             t1->Next = t2;             t3->Next = temp;             t2->Next = t3; } 

全部代码：

#include <stdio.h> #include <malloc.h> typedef struct node { int Score; struct node * Next; }Node, * List; void Insert(List *L, Node e) {     List temp = *L;     List n = (List)malloc(sizeof(Node));     n->Score = e.Score; if (temp == NULL) { *L = n; } else { while (temp->Next != NULL) {             temp = temp->Next; }         temp->Next = n; }     n->Next = NULL; } void Swap(List * L, int i, int j) {     List temp = *L;     List t1;     List t2;     List t3;     List t4;     List t5; int m; /*i和j为1时情况比较特殊，需要让表头重新指向交换后的那个节点*/ if (i == 1) {          t1 = *L; for (m = 1; temp->Next != NULL; m++, temp = temp->Next) { if (m + 1 == j) { *L = temp->Next;                 t2 = temp->Next->Next;                 temp->Next->Next = t1->Next;                 t1->Next = t2;                 temp->Next = t1; } } } if (j == 1) {         t1 = *L; for (m = 1; temp->Next != NULL; m++, temp = temp->Next) { if (m + 1 == i) { *L = temp->Next;                 t2 = temp->Next->Next;                 temp->Next->Next = t1->Next;                 t1->Next = t2;                 temp->Next = t1; } } } /*相邻节点之间交换和非相邻结点之间交换不一样*/ else { if ((i - j) != 1 && (j- i) != 1) {//非相邻结点之间交换 for (m = 1; temp->Next != NULL; m++, temp = temp->Next) { if (m + 1 == i) {                     t1 = temp; } if (m + 1 == j) {                     t2 = temp; } }             t5 = t1->Next->Next;             t3 = t1->Next;             t4 = t2->Next;             t1->Next = t4;             t2->Next = t3;             t3->Next = t4->Next;             t4->Next = t5; } else if (i < j) {//相邻节点之间交换 for (m = 1; temp != NULL; m++, temp = temp->Next) { if (m + 1 == i) {                     t1 = temp; } if (m == j) {                     t2 = temp; } }             temp = t2->Next;             t3 = t1->Next;             t1->Next = t2;             t3->Next = temp;             t2->Next = t3; } else if (i > j) { for (m = 1; temp != NULL; m++, temp = temp->Next) { if (m + 1 == j) {                     t1 = temp; } if (m == i) {                     t2 = temp; } }             temp = t2->Next;             t3 = t1->Next;             t1->Next = t2;             t3->Next = temp;             t2->Next = t3; } } } void printflist(List list) {     List temp; for (temp = list; temp != NULL; temp = temp->Next) { printf("%dn", temp->Score); } } void freelist(List *list) {     List temp = *list, del; while (temp != NULL) {         del = temp;         temp = temp->Next; free(del); } } int main() {     List list = NULL;     Node n1, n2, n3, n4, e;//定义5个节点     e.Score = 5;     n1.Score = 1;     n2.Score = 2;     n3.Score = 3;     n4.Score = 4; Insert(&list, n1); Insert(&list, n2); Insert(&list, n3); Insert(&list, n4); Insert(&list, e); // dellist(&list, 8); Swap(&list, 5, 4); printflist(list); freelist(&list); return 0; }