Java Stack Data Structure.pptx

Java Stack Data Structure.pptx

• 1.
  Java Stack DataStructure
• 2.
  Java Stack Class The Java collections framework has a class named Stack that provides the functionality of the stack data structure.  The Stack class extends the Vector class.
• 3.
  Stack Implementation  Instack, elements are stored and accessed in Last In First Out manner. That is, elements are added to the top of the stack and removed from the top of the stack.
• 4.
  Creating a Stack In order to create a stack, we must import the java.util.Stack package first. Once we import the package, here is how we can create a stack in Java. Stack<Type> stacks = new Stack<>(); Here, Type indicates the stack's type. For example, // Create Integer type stack Stack<Integer> stacks = new Stack<>(); // Create String type stack Stack<String> stacks = new Stack<>();
• 5.
  Stack Methods  SinceStack extends the Vector class, it inherits all the methods Vector.  Besides these methods, the Stack class includes 5 more methods that distinguish it from Vector.
• 6.
  push() Method  Toadd an element to the top of the stack, we use the push() method. For example import java.util.Stack; class Main { public static void main(String[] args) { Stack<String> animals= new Stack<>(); // Add elements to Stack animals.push("Dog"); animals.push("Horse"); animals.push("Cat"); System.out.println("Stack: " + animals); } }
• 7.
  pop() Method import java.util.Stack; classMain { public static void main(String[] args) { Stack<String> animals= new Stack<>(); // Add elements to Stack animals.push("Dog"); animals.push("Horse"); animals.push("Cat"); System.out.println("Initial Stack: " + animals); // Remove element stacks String element = animals.pop(); System.out.println("Removed Element: " + element); } }
• 8.
  search() Method  tosearch an element in the stack, we use the search() method. It returns the position of the element from the top of the stack. For example, import java.util.Stack; class Main { public static void main(String[] args) { Stack<String> animals= new Stack<>(); // Add elements to Stack animals.push("Dog"); animals.push("Horse"); animals.push("Cat"); System.out.println("Stack: " + animals); // Search an elemen t int position = animals.search("Horse"); System.out.println("Position of Horse: " + position); } }
• 9.
  empty() Method  Tocheck whether a stack is empty or not, we use the empty() method. For example, import java.util.Stack; class Main { public static void main(String[] args) { Stack<String> animals= new Stack<>(); // Add elements to Stack animals.push("Dog"); animals.push("Horse"); animals.push("Cat"); System.out.println("Stack: " + animals); // Check if stack is empty boolean result = animals.empty(); System.out.println("Is the stack empty? " + result); } }