bb.cpp

#include <stdio.h>
#include <stdlib.h>
typedef struct node{
	char value;
	struct node* parent;
	struct node* left, *right;
}node;
typedef node* p_node;

void inorder(p_node node){
	if( node == NULL ) return;
	inorder(node->left);
	printf("%c ", node->value);
	inorder(node->right);
}
void preorder(p_node node){
	if( node == NULL ) return;
	printf("%c ", node->value);
	preorder(node->left);
	preorder(node->right);
}
void postorder(p_node node){
	if( node == NULL ) return;
	postorder(node->left);
	postorder(node->right);
	printf("%c ", node->value);
}
int main()
{
	p_node root = (p_node)malloc(sizeof(node));
	root->value = '.';
	root->parent = root->left = root->right = NULL;
	
	root->left = (p_node)malloc(sizeof(node));
	root->left->value = 'L';
	root->left->parent = root;
	root->left->left = root->left->right = NULL;
	
	p_node newNode = (p_node)malloc(sizeof(node));
	newNode->value = 'U';
	newNode->parent = root;
	newNode->left = newNode->right = NULL;
	root->right = newNode;
	
	newNode = (p_node)malloc(sizeof(node));
	newNode->value = 'A';
	newNode->parent = root->left;
	newNode->left = newNode->right = NULL;
	root->left->left = newNode;
	
	newNode = (p_node)malloc(sizeof(node));
	newNode->value = 'B';
	newNode->parent = root->left;
	newNode->left = newNode->right = NULL;
	root->left->right = newNode;
	
	newNode = (p_node)malloc(sizeof(node));
	newNode->value = 'X';
	newNode->parent = root->right;
	newNode->left = newNode->right = NULL;
	root->right->left = newNode;
	
	newNode = (p_node)malloc(sizeof(node));
	newNode->value = 'Y';
	newNode->parent = root->right;
	newNode->left = newNode->right = NULL;
	root->right->right = newNode;
	// L1, L2, U1, U2
	
	printf("전위순회 : ");
	preorder(root); 
	
	printf("\n중위순회 : ");
	inorder(root);
	
	printf("\n후위순회 : ");
	postorder(root);
	printf("\n%c",root->value);
}

file.cpp

#include <stdio.h>

int main()
{
	int n;
	char arr[] = "input.txt";
	FILE *in = fopen(arr, "r");// read
	FILE *out = fopen("output.txt", "a");//write
	//append
	fscanf(in, "%d", &n);
	fprintf(out, "%d", n);\
	fclose(in);
	fclose(out);
}