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StackDemo.java
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111 lines (98 loc) · 2.9 KB
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import java.util.Scanner;
class Stack {
private int top;
private int capacity;
private int[] stackArray;
// Constructor
public Stack(int size) {
capacity = size;
stackArray = new int[capacity];
top = -1; // empty stack
}
// Push an element
public void push(int value) {
if (isFull()) {
System.out.println("Stack Overflow! Cannot push " + value);
return;
}
stackArray[++top] = value;
System.out.println(value + " pushed to stack.");
}
// Pop an element
public int pop() {
if (isEmpty()) {
System.out.println("Stack Underflow! Nothing to pop.");
return -1;
}
int value = stackArray[top--];
System.out.println(value + " popped from stack.");
return value;
}
// Peek (top element)
public int peek() {
if (isEmpty()) {
System.out.println("Stack is empty!");
return -1;
}
return stackArray[top];
}
// Check if stack is empty
public boolean isEmpty() {
return top == -1;
}
// Check if stack is full
public boolean isFull() {
return top == capacity - 1;
}
// Display elements
public void display() {
if (isEmpty()) {
System.out.println("Stack is empty!");
return;
}
System.out.print("Stack elements (top → bottom): ");
for (int i = top; i >= 0; i--) {
System.out.print(stackArray[i] + " ");
}
System.out.println();
}
}
public class StackDemo {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
System.out.print("Enter stack size: ");
int size = sc.nextInt();
Stack stack = new Stack(size);
while (true) {
System.out.println("\n1. Push");
System.out.println("2. Pop");
System.out.println("3. Peek");
System.out.println("4. Display");
System.out.println("5. Exit");
System.out.print("Enter your choice: ");
int choice = sc.nextInt();
switch (choice) {
case 1:
System.out.print("Enter value to push: ");
int val = sc.nextInt();
stack.push(val);
break;
case 2:
stack.pop();
break;
case 3:
System.out.println("Top element: " + stack.peek());
break;
case 4:
stack.display();
break;
case 5:
System.out.println("Exiting...");
sc.close();
System.exit(0);
default:
System.out.println("Invalid choice!");
}
}
}
}