1// Aim: Program to perform Binary Tree operations (Array representation).
2#include <stdio.h>
3#include <stdlib.h>
4int a[15], i, item, key, ch, loc;
5void display() {
6    for (i = 0; i < 15; i++) {
7        if (a[i] != -1) {
8            printf("%d ", a[i]);
9        } else {
10            printf("- ");}}
11    printf("\n");}
12
13
14void build(int index) {
15    if (index >= 15)
16        return;
17    printf("\nEnter item: ");
18    scanf("%d", &a[index]);
19    printf("\nWant to create left child for %d? If yes, enter 0: ", a[index]);
20    scanf("%d", &ch);
21    if (ch == 0) {
22        build(2 * index + 1);}
23    printf("\nWant to create right child for %d? If yes, enter 0: ", a[index]);
24    scanf("%d", &ch);
25    if (ch == 0) {
26        build(2 * index + 2);}}
27
28
29int search(int index) {
30    if (index < 15) {
31        if (a[index] == key) {
32            loc = index;
33            return 1;
34        } else {
35            if (search(2 * index + 1) || search(2 * index + 2)) {
36                return 1;}}}
37    return 0;}
38
39
40void insert() {
41    printf("\nEnter item to insert: ");
42    scanf("%d", &item);
43    printf("\nWant to insert %d as left child of %d? If yes, enter 0: ", item, key);
44    scanf("%d", &ch);
45    if (ch == 0) {
46        if (a[2 * loc + 1] == -1) {
47            a[2 * loc + 1] = item;
48        } else {
49            printf("\nLeft child exists");}
50    } else {
51        printf("\nWant to insert %d as right child of %d? If yes, enter 0: ", item, key);
52        scanf("%d", &ch);
53        if (ch == 0) {
54            if (a[2 * loc + 2] == -1) {
55                a[2 * loc + 2] = item;
56            } else {
57                printf("\nRight child exists");}}}}
58
59
60void delete() {
61    printf("\nEnter key to delete: ");
62    scanf("%d", &key);
63    loc = -1;
64    if (search(0)) {
65        if (a[2 * loc + 1] == -1 && a[2 * loc + 2] == -1) {
66            a[loc] = -1;
67        } else {
68            printf("\nNot a leaf, deletion denied");}
69    } else {
70        printf("\nKey not found");}}
71
72        
73int main(void) {
74    int choice;
75    for (i = 0; i < 15; i++) {
76        a[i] = -1;}
77    while (1) {
78        printf("\nMenu:\n");
79        printf("1. Build Tree\n2. Display Tree\n3. Search Key\n4. Insert Item\n5. Delete Item\n6. Exit\nEnter your choice: ");
80        scanf("%d", &choice);
81        switch (choice) {
82            case 1:
83                build(0);
84                break;
85            case 2:
86                printf("Tree is:\n");
87                display();
88                break;
89            case 3:
90                printf("\nEnter key to search: ");
91                scanf("%d", &key);
92                loc = -1;
93                if (search(0))
94                    printf("\nKey found at index %d....", loc);
95                else
96                    printf("\nKey not found....");
97                break;
98            case 4:
99                printf("\nEnter key to search for insertion: ");
100                scanf("%d", &key);
101                loc = -1;
102                if (search(0)) {
103                    insert();
104                } else {
105                    printf("\nKey not found, cannot insert");}
106                break;
107            case 5:
108                delete();
109                break;
110            case 6:
111                exit(0);
112            default:
113                printf("Invalid choice! Please enter a valid option.\n");}}
114    return 0;}