3.2

#include <stdio.h>
#include <stdlib.h>

// Осуществить нерекурсивный проход по бинарному дереву,
// чтобы печатался сначала предок, а потом потомок.

struct tree{
    int value;
    struct tree *left;
    struct tree *right;
};

struct stack{
    struct tree *node;
    struct stack *next;
};

void makeTree(struct tree* node){
    node -> value = 100;
    node -> left = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> value = 70;
    node -> left -> left = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> value = 50;
    node -> left -> left -> left = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> left -> value = 10;
    node -> left -> left -> left -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> left -> right -> value = 40;
    node -> left -> left -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> right -> value = 55;
    node -> left -> left -> right -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> right -> right -> value = 60;
    node -> left -> left -> right -> right -> left = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> right -> right -> left -> value = 58;
    node -> left -> left -> right -> right -> right= (struct tree*) malloc(sizeof(struct tree));
    node -> left -> left -> right -> right -> right -> value = 65;
    node -> left -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> left -> right -> value = 90;
    node -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> right -> value = 150;
    node -> right -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> right -> right -> value = 200;
    node -> right -> right -> left = (struct tree*) malloc(sizeof(struct tree));
    node -> right -> right -> left -> value = 170;
    node -> right -> right -> right = (struct tree*) malloc(sizeof(struct tree));
    node -> right -> right -> right -> value = 210;
}

void showTree(struct tree* node){
    if(!node){
        printf("error\n");
        exit(1);
    }
    int flag = 1;
    struct stack *stackEl = (struct stack*) calloc(1, sizeof(struct stack));
    stackEl -> node = node;
    struct stack *stackPtr = NULL;
    stackEl -> next = stackPtr;
    printf("Node stores: %d\n", node -> value);
    while (stackEl || node -> right){
        do {
            if (flag && node -> left){
                node = node -> left;
            } else {
                if (node -> right){
                    node = node -> right;
                }
            }
            flag = 1;
            if (node -> left && node -> right){
                stackPtr = stackEl;
                stackEl = (struct stack*) malloc(sizeof(struct stack));
                stackEl -> node = node;
                stackEl -> next = stackPtr;
            }
            printf("Node stores: %d\n", node -> value);
        } while (node -> left || node -> right);
        if (stackEl){
            node = stackEl -> node;
            stackPtr = stackEl -> next;
            free(stackEl);
        }
        stackEl = stackPtr;
        if (node -> right){
            flag = 0;
        }
    }
}

void showTreeRec(struct tree* node, int depth){
    if (node) {
        showTreeRec(node -> right, depth + 1);
    }
    for (int i = 0; i < depth; i++) {
        printf("      ");
    }
    if (node){
        printf("%d\n", node -> value);
    } else {
        printf("#\n");
    }
    if (node){
        showTreeRec(node -> left, depth + 1);
    }
}


int main(){
    struct tree *root = (struct tree*) malloc (sizeof(struct tree));
    makeTree(root);
    showTreeRec(root, 0);
    showTree(root);
    return 0;
}