Paranthesizer using stack

Author: ShehaniHettiarachchi

Basics/Data Structure/Stack-Paranthesizer/Paranthesizer.java

@@ -0,0 +1,46 @@
+package Stack;
+
+import java.util.Scanner;
+
+public class Paranthesizer {
+static String expr;
+ public static void main(String[] args) {
+ Scanner sc = new Scanner(System.in);
+ System.out.println("Enter your expression : ");
+ expr = sc.nextLine();
+ boolean res = checker();
+ System.out.println(res?"Valid Expression":"Invalid Expression");
+ sc.close();
+ }
+
+ public static int countParanthesis(){
+ int count = 0;
+ for (int i = 0; i < expr.length(); i++) {
+ if (expr.charAt(i) == '(' || expr.charAt(i) == '{' || expr.charAt(i) == '[') {
+ count++;
+ }
+ }
+
+ return count;
+ }
+
+ public static boolean checker(){
+ StackX stk = new StackX(countParanthesis());
+
+ for (char element : expr.toCharArray()) {
+ if(element == '(' || element == '{' || element == '['){
+ stk.push(element);
+ }
+ 
+ if (element == ')' && stk.peek() == '(') {
+ stk.pop();
+ }else if (element == '}' && stk.peek() == '{') {
+ stk.pop();
+ }else if (element == ']' && stk.peek() == '[') {
+ stk.pop();
+ }
+ }
+
+ return stk.isEmpty();
+ }
+}

Basics/Data Structure/Stack-Paranthesizer/StackX.java

@@ -0,0 +1,56 @@
+package Stack;
+
+public class StackX {
+private char[] data; //stack array
+private int top; //top of the stack
+private int size; //size of stack array
+
+ public StackX(int size){
+ this.size = size;
+ data = new char[size];
+ top = -1;
+ }
+
+ //push method
+ public boolean push(char element){
+ if (top < size - 1) {
+ data[++top] = element;
+ return true;
+ }
+
+ return false;
+
+ }
+
+ public char pop(){
+ if (top != -1) {
+ return data[top--];
+ }
+
+ return ' ';
+ }
+
+ public char peek(){
+ if (top != -1) {
+ return data[top];
+ }
+
+ return ' ';
+ }
+
+ public boolean isFull(){
+ if (top == size - 1) {
+ return true;
+ }
+
+ return false;
+ }
+
+ public boolean isEmpty(){
+ if (top == -1) {
+ return true;
+ }
+
+ return false;
+ }
+}