first

#include <stdio.h>
#include <malloc.h>
#include <string.h>

struct binary_tree{
    int root;
    struct binary_tree *left, *right;
};
struct binary_tree* new_binary_tree(int x){
    struct binary_tree *p;
    p =(struct binary_tree*) malloc(sizeof(struct binary_tree));
    p->root= x;
    p->left = NULL;
    p->right = NULL;
    return p;
}
void inorderPref(struct binary_tree *root)
{
    if(root!=NULL)
    {
        printf("%d ", root->root);
        inorderPref(root->left);
        inorderPref(root->right);
    }
}
void inorderPost(struct binary_tree *root)
{
    if(root!=NULL)
    {
        inorderPost(root->left);
        inorderPost(root->right);
        printf("%d ", root->root);
    }
}
struct binary_tree* insert(struct binary_tree *root, int x){
    if(root==NULL)
        return new_binary_tree(x);
    else
        if(x>root->root)
            root->right = insert(root->right, x);
    else
        if (x < root->root)
            root->left = insert(root->left,x);
    return root;
}

int main(){
    struct binary_tree *root;
    FILE *file;
    file = fopen("input.txt", "r");
    int n;
    fscanf(file, "%d", &n);
    root = new_binary_tree(n);
    while (fscanf(file, "%d", &n)==1){
        insert(root, n);
    }
    inorderPref(root);
    printf("\n");
    inorderPost(root);
    return 0;
}