/* file name: binaryTreeSort.c */
/* 二元樹排序 */

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

struct data {
    int num;
    struct data *lbaby, *rbaby;
} *root, *tree, *leaves;

void find(int, struct data *);
void output(struct data *);
void printDashLine(void);

int main()
{
    int data[10] = {75, 23, 98, 44, 57, 12, 29, 64, 38, 82};
    int i;
    printf("\n<< Binary tree sort >>\n");
    printf("\n未排序的資料: ");
    for (i = 0; i < 10; i++)
        printf("%d  ", data[i]);
    printf("\n");
    
    printDashLine();
    root = (struct data *) malloc(sizeof(struct data));
    root->num = data[0];     /* 建樹根 */
    root->lbaby = NULL;
    root->rbaby = NULL;
    printf("\n#%2d Step : ", 1);
    output(root);
    leaves = (struct data *) malloc(sizeof(struct data));
    for (i = 1; i < 10; i++) { /* 建樹枝 */
        leaves->num = data[i];
        leaves->lbaby = NULL;
        leaves->rbaby = NULL;
        find(leaves->num, root);
        if (leaves->num > tree->num)  /* 若比父節點大，則放右子樹 */
            tree->rbaby = leaves;
        else                        /* 否則放在左子樹 */
            tree->lbaby = leaves;
        printf("\n#%3d Step : ", i+1);
        output(root);
        leaves = (struct data *) malloc(sizeof(struct data));
    }
    puts("");
    printDashLine();
    printf("\n由小至大排序後的資料 : ");
    output(root);
    printf("\n");

    return 0;
}

/* 尋找新節點存放的位置 */
void find(int input, struct data *papa)
{
    if ((input > papa->num) && (papa->rbaby != NULL))
        find(input, papa->rbaby);
    else if ((input < papa->num) && (papa->lbaby != NULL))
        find(input, papa->lbaby);
    else
        tree = papa;
}

/* 用中序追蹤將資料印出 */
void output(struct data *node)
{
    if (node != NULL) {
        output(node->lbaby);
        printf("%d  ", node->num);
        output(node->rbaby);
    }
}

void printDashLine()
{
    for(int i = 0; i < 58; i++)
        printf("-");
}