Data Structures: Stack, Queue, Linked List, BST

ds_operations.c

@@ -0,0 +1,101 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#define MAX 100
+
+int stack[MAX], top = -1;
+int queue[MAX], front = -1, rear = -1;
+
+struct Node {
+    int data;
+    struct Node* next;
+};
+
+struct Node* head = NULL;
+
+struct BST {
+    int data;
+    struct BST* left;
+    struct BST* right;
+};
+
+struct BST* root = NULL;
+
+void push(int x) {
+    if (top == MAX-1) return;
+    stack[++top] = x;
+}
+
+int pop() {
+    if (top == -1) return -1;
+    return stack[top--];
+}
+
+void enqueue(int x) {
+    if (rear == MAX-1) return;
+    if (front == -1) front = 0;
+    queue[++rear] = x;
+}
+
+int dequeue() {
+    if (front == -1 || front > rear) return -1;
+    return queue[front++];
+}
+
+void insertList(int x) {
+    struct Node* n = malloc(sizeof(struct Node));
+    n->data = x;
+    n->next = head;
+    head = n;
+}
+
+void displayList() {
+    struct Node* t = head;
+    while (t) {
+        printf("%d ", t->data);
+        t = t->next;
+    }
+    printf("\n");
+}
+
+struct BST* insertBST(struct BST* r, int x) {
+    if (!r) {
+        r = malloc(sizeof(struct BST));
+        r->data = x;
+        r->left = r->right = NULL;
+        return r;
+    }
+    if (x < r->data) r->left = insertBST(r->left, x);
+    else r->right = insertBST(r->right, x);
+    return r;
+}
+
+void inorder(struct BST* r) {
+    if (!r) return;
+    inorder(r->left);
+    printf("%d ", r->data);
+    inorder(r->right);
+}
+
+int main() {
+    int ch, x;
+    while (1) {
+        printf("\n1 Push\n2 Pop\n3 Enqueue\n4 Dequeue\n5 Insert Linked List\n6 Display Linked List\n7 Insert BST\n8 Display BST (Inorder)\n9 Exit\n");
+        scanf("%d", &ch);
+
+        if (ch == 9) break;
+
+        switch (ch) {
+            case 1: scanf("%d", &x); push(x); break;
+            case 2: printf("%d\n", pop()); break;
+            case 3: scanf("%d", &x); enqueue(x); break;
+            case 4: printf("%d\n", dequeue()); break;
+            case 5: scanf("%d", &x); insertList(x); break;
+            case 6: displayList(); break;
+            case 7: scanf("%d", &x); root = insertBST(root, x); break;
+            case 8: inorder(root); printf("\n"); break;
+            default: break;
+        }
+    }
+    return 0;
+}