createBinaryTree给出无限循环，createBinarySearchTree给出分段错误。当我刚接触数据结构时，有人可以指导我。
#include <stdio.h>
#include <stdlib.h>
typedef struct node
{
int data;
struct node *lchild;
struct node *rchild;
} * NODE;
NODE createBinaryTree(NODE root)
{
NODE temp = (NODE)malloc(sizeof(struct node));
printf("Enter the value of the node. \n Enter -1 for returning. \n");
scanf(" %d", &temp->data);
if (temp->data == -1)
return NULL;
else
{
printf("For left Node of %d \n", temp->data);
temp->lchild = createBinaryTree(temp->lchild);
printf("For right Node of %d \n", temp->data);
temp->rchild = createBinaryTree(temp->rchild);
}
return temp;
}
NODE createBinarySearchTree(NODE root, int ele)
{
NODE new_node;
new_node = (NODE)malloc(sizeof(struct node));
new_node->data = ele;
new_node->lchild = new_node = NULL;
if (root == NULL)
return new_node;
NODE parent = NULL;
NODE curr = root;
while (curr != NULL)
{
parent = curr;
if (curr->data < ele)
curr = curr->rchild;
else
curr = curr->lchild;
}
if (ele < parent->data)
parent->lchild = new_node;
else
parent->rchild = new_node;
return root;
}
void inorder(NODE ptr)
{
if (ptr != NULL)
{
inorder(ptr->lchild);
printf("%5d", ptr->data);
inorder(ptr->rchild);
}
}
void postorder(NODE ptr)
{
if (ptr != NULL)
{
postorder(ptr->lchild);
postorder(ptr->rchild);
printf("%5d", ptr->data);
}
}
void preorder(NODE ptr)
{
if (ptr != NULL)
{
printf("%5d", ptr->data);
preorder(ptr->lchild);
preorder(ptr->rchild);
}
}
void main()
{
NODE root = NULL;
printf("Enter 0.createBinaryTree \n");
printf("Enter 1.createBinarySearchTree \n");
printf("Enter 2.displayTree \n");
printf("Enter 3.searchTree \n");
int choice;
printf("Enter your choice\n");
scanf(" %d", &choice);
int tempvalue;
while (1)
{
switch (choice)
{
case 0:
root = createBinaryTree(root);
break;
case 1:
printf("Enter Root Node\n");
scanf(" %d", &tempvalue);
while (tempvalue != -1)
{
root = createBinarySearchTree(root, tempvalue);
break;
printf("Enter Next Node.\n Enter -1 to exit\n");
scanf(" %d", &tempvalue);
}
break;
case 2:
printf("\n Inorder Traversals \n");
inorder(root);
printf("\n Postorder Traversals \n");
postorder(root);
printf("\n Preorder Traversals \n");
preorder(root);
printf("\n ********* \n");
break;
case 4:
exit(0);
}
}
}
对于BinarySearchTree。在第一次迭代中，在每次迭代中都将新节点设置为NULL。最好先检查节点的值，然后确定遍历树的方向。当您击中根节点时，添加节点。类似于以下内容。
分别输入root的输入，以便您可以比较下一个输入。
case 1:
printf("Enter Root Node\n");
scanf(" %d", &tempvalue);
NODE root;
root = (NODE)malloc(sizeof(struct node));
root->data = tempvalue;
while (tempvalue != -1)
{
printf("Enter Node Value\n");
scanf(" %d", &value);
if(value == -1){
break;
}
root = createBinarySearchTree(root, value);
}
return 0;
然后在函数内部，遍历树，直到找到节点应该去的地方。
NODE createBinarySearchTree(NODE root, int ele)
{
NODE new_node;
new_node = (NODE)malloc(sizeof(struct node));
new_node->data = ele;
if (root == NULL)
return new_node;
NODE curr = root;
while (curr != NULL)
{
printf("%d\n",curr->data);
if(ele < curr->data )
{
if(curr->lchild == NULL){
printf("inserted %d as left child of %d\n",ele,curr->data );
curr->lchild = new_node;
return root;
}
curr=curr->lchild;
}
else if(ele > curr->data)
{
if(curr->rchild == NULL){
printf("inserted %d as right child child of %d\n",ele,curr->data );
curr->rchild = new_node;
return root;
}
curr=curr->rchild;
}
}
return root;
}
对于您的createBinaryTree函数
问题出在scanf（“％d”，＆temp-> data）行；当您到达树的根时，然后再次在根上方的节点上调用create二叉树，然后覆盖先前的条目。为了解决这个问题，您应该先检查scanf的值，然后再将其分配给temp-> data。同样，如果在上一次迭代中设置了root，则需要返回root而不是在-1上返回NULL。类似以下内容。
编辑
typedef struct node
{
int data;
struct node *lchild;
struct node *rchild;
} * NODE;
NODE createBinaryTree(NODE root)
{
printf("Enter the value of the node. \n Enter -1 for returning. \n");
int input = 0;
scanf(" %d", &input);
printf("%d\n",input );
if(input == -1 && root == NULL){
return NULL;
}
if(input == -1 && root != NULL){
return root;
}
NODE temp = (NODE)malloc(sizeof(struct node));
temp->data = input;
if (temp->data == -1)
return NULL;
else
{
printf("For left Node of %d \n", temp->data);
temp->lchild = createBinaryTree(temp->lchild);
printf("For right Node of %d \n", temp->data);
temp->rchild = createBinaryTree(temp->rchild);
}
return temp;
}
NODE createBinarySearchTree(NODE root, int ele)
{
NODE new_node;
new_node = (NODE)malloc(sizeof(struct node));
new_node->data = ele;
new_node->lchild = new_node;
if (root == NULL)
return new_node;
NODE parent = NULL;
NODE curr = root;
while (curr != NULL)
{
parent = curr;
if (curr->data < ele)
curr = curr->rchild;
else
curr = curr->lchild;
}
if (ele < parent->data)
parent->lchild = new_node;
else
parent->rchild = new_node;
return root;
}
void inorder(NODE ptr)
{
if (ptr != NULL)
{
inorder(ptr->lchild);
printf("%5d", ptr->data);
inorder(ptr->rchild);
}
}
void postorder(NODE ptr)
{
if (ptr != NULL)
{
postorder(ptr->lchild);
postorder(ptr->rchild);
printf("%5d", ptr->data);
}
}
void preorder(NODE ptr)
{
if (ptr != NULL)
{
printf("%5d", ptr->data);
preorder(ptr->lchild);
preorder(ptr->rchild);
}
}
int main()
{
NODE root = NULL;
printf("Enter 0.createBinaryTree \n");
printf("Enter 1.createBinarySearchTree \n");
printf("Enter 2.displayTree \n");
printf("Enter 3.searchTree \n");
int choice;
printf("Enter your choice\n");
scanf(" %d", &choice);
int tempvalue;
while (1)
{
switch (choice)
{
case 0:
root = createBinaryTree(root);
printf("Done\n");
return 0;
case 1:
printf("Enter Root Node\n");
scanf(" %d", &tempvalue);
while (tempvalue != -1)
{
root = createBinarySearchTree(root, tempvalue);
break;
printf("Enter Next Node.\n Enter -1 to exit\n");
scanf(" %d", &tempvalue);
}
return 0;
case 2:
printf("\n Inorder Traversals \n");
inorder(root);
printf("\n Postorder Traversals \n");
postorder(root);
printf("\n Preorder Traversals \n");
preorder(root);
printf("\n ********* \n");
return 0;
case 4:
exit(0);
}
}
return 0;
}