纯C创建二叉树及二叉树的遍历

#include <stdio.h>
#include <malloc.h>
typedef struct TreeNode Tree;
struct TreeNode{
int value;
int level;//level
Tree *leftChild;
Tree *rightChild;
Tree *parent;
};
Tree *SetChild(int value,Tree *parentT);//ok
void View_Tree(Tree *pThis);//ok
void mk_space(int nums);
int main()
{
Tree *k;
Tree *moveon;
//Tree *t;
int inValue=0,c_val=0;
//creat a tree(init k)
k=(Tree *)malloc(sizeof(Tree));//k as top,do not change
k->parent=NULL;//the top point has no parent
k->level=0;
moveon=k;//save k's location for use
printf("input the value of the first item:");
scanf("%d",&inValue);
moveon->value=inValue;
while(inValue>0 || c_val!=4)
{
printf("input left value of %d:",moveon->value);
scanf("%d",&inValue);//set value
if(inValue>0)
moveon->leftChild=SetChild(inValue,moveon);
printf("input right value of %d:",moveon->value);
scanf("%d",&inValue);
if(inValue>0)
moveon->rightChild=SetChild(inValue,moveon);
printf("next?\nif go up,input 1\nif go to left child,input 2\nif goto right child,input 3\nif exit,input 4\ninput:");
scanf("%d",&c_val);
if(c_val==1){
if(moveon->parent==NULL) break;
moveon=moveon->parent;
}else if(c_val==2){
moveon=moveon->leftChild;
}
else if(c_val==3){
moveon=moveon->rightChild;
}
else if(c_val==4){
break;//跳出循环
}
}
if(inValue==0) return 0;
//开始遍历
View_Tree(k);

free(k);
}
Tree *SetChild(int value,Tree *parentT)//ok
{
Tree *ks=(Tree *)malloc(sizeof(Tree));
ks->value=value;//set value
ks->parent=parentT;//set parent point to go back
ks->leftChild=NULL;//left and
ks->rightChild=NULL;//right are set null
ks->level=parentT->level+1;
return ks;
}
void View_Tree(Tree *pThis)
{
mk_space(pThis->level);
printf("%d\n",pThis->value);
if(pThis->leftChild!=NULL)
{
View_Tree(pThis->leftChild);
}
if(pThis->rightChild!=NULL)
{
View_Tree(pThis->rightChild);
}
}
void mk_space(int nums)
{
int k;
for(k=0;k<nums*2;k++)
{
printf(" ");
}
}