LinkedStackDemoClass.java

//Alec Arroyo 
/**
 * Infix to Postfix converter
 * Postfix to Infix converter
 * Prints Equations
 * Exits program
**/
import java.util.Scanner;
import java.util.Stack;
 
public class LinkedStackDemoClass<T> extends LinkedStackClass<T>
{
 public static void main(String[] args) 
 {
 /** Declared all stacks and linked lists **/
 //Stack for num = 1
 LinkedStackClass<String> stack = new LinkedStackClass();
 //Stack for num = 2
 LinkedStackClass<String> s = new LinkedStackClass();
 //Stack linked list to print all equaitons
 LinkedStackClass<String> allEqu = new LinkedStackClass();
 //Stack linked list to print all conversions
 LinkedStackClass<String> linked = new LinkedStackClass();
 
 //Declared string variables 
 String value1, end;
 //Declared num variable; holds user input for number option.
 int num = 0;
 //Declared string
 String linkval = ""; 
 Scanner keyboard = new Scanner(System.in);
 
 //Keep looping until user wants to exit(4)
 while (num != 4)
 { 
 String word1 = "";
 String word2 = ""; 
 char c = 'a';
 char p = 'b';
 boolean value = stack.isEmptyStack();
 
 //Asks user to input option number
 System.out.println();
 System.out.println("Please select what type of conversion you would like to do: ");
 System.out.println("1.Infix to postfix");
 System.out.println("2.Postfix to infix");
 System.out.println("3.Print Equations");
 System.out.println("4.Exit");
 num = keyboard.nextInt();
 
 //Option #1
 if(num == 1)
 {
 System.out.println("Enter equation without the x = portion of it for infix.(add ; at end) ");
 word1 = keyboard.next();
 
 //Error checking if user puts semicolon at end
 if(!word1.contains(";"))
 {
 System.out.println("Error no ; variable at the end of equation. Try again");
 System.exit(0);
 }
 //Push equation onto stack
 allEqu.push(word1);
 int next = 0;
 for(int i = 0; i <= next; i++)
 {
 c = word1.charAt(i);
 
 if(c != ';')
 {
 
 if(c == '^' || c == '*' || c == '/' || c == '+' || c == '-')
 {
 if(value == true)
 {
 String a_letter = Character.toString(c);
 stack.push(a_letter);
 value = false;
 }
 else if(value == false)
 {
 String a_letter = Character.toString(c);
 if(stack.peek().equals(a_letter))
 { 
 System.out.print(stack.peek());
 linkval = linkval + stack.peek();
 stack.pop();
 stack.push(a_letter);
 }
 else if(stack.peek().equals("+") && a_letter.equals("-"))
 {
 System.out.print(stack.peek());
 linkval = linkval + stack.peek();
 stack.pop();
 stack.push(a_letter);
 }
 else if(stack.peek().equals("-") && a_letter.equals("+"))
 {
 System.out.print(stack.peek());
 linkval = linkval + stack.peek();
 stack.pop();
 stack.push(a_letter);
 }
 else if(stack.peek().equals("*") && a_letter.equals("/"))
 {
 System.out.print(stack.peek());
 linkval = linkval + stack.peek();
 stack.pop();
 stack.push(a_letter);
 }
 else if(stack.peek().equals("/") && a_letter.equals("*"))
 {
 System.out.print(stack.peek());
 linkval = linkval + stack.peek();
 stack.pop();
 stack.push(a_letter);
 }
 else
 {
 stack.push(a_letter);
 }
 }
 }
 else
 {
 System.out.print(c);
 linkval = linkval + c;
 }
 next++;
 }
 else
 {
 //Prints postfix notation; stores in linked list
 while (!stack.isEmptyStack()) { 
 System.out.print(stack.peek());
 linkval = linkval + stack.peek();
 stack.pop();
 
 if(stack.first == null)
 {
 linked.push(linkval);
 linkval = "";
 }
 }
 }
 }
 }
 //Option #2
 else if(num == 2)
 {
 value = true;
 System.out.println("Enter equation without the x = portion of it for postfix.(add ; at end) ");
 word2 = keyboard.next();
 if(!word2.contains(";"))
 {
 System.out.println("Error no ; variable at the end of equation. Try again");
 System.exit(0);
 }
 allEqu.push(word2);
 int nex = 0;
 for(int i = 0; i <= nex; i++)
 {
 p = word2.charAt(i);
 
 if(p != ';')
 {
 if(p != '^' && p != '*' && p != '/' && p != '+' && p != '-')
 {
 String a_letter = Character.toString(p);
 s.push(a_letter);
 }
 else
 { 
 String a_letter = Character.toString(p);
 if(value == true)
 {
 System.out.print(s.peek());
 linkval = linkval + s.peek();
 s.pop();
 s.push(a_letter);
 System.out.print(a_letter);
 linkval = linkval + a_letter;
 s.pop();
 System.out.print(s.peek());
 linkval = linkval + s.peek();
 value = false;
 }
 else
 {
 s.push(a_letter);
 }
 }
 nex++;
 }
 else
 {
 //Prints infix notation; stores in linked list
 while(!s.isEmptyStack())
 {
 System.out.print(p);
 linkval = linkval + p;
 s.pop();
 }
 if(s.first == null)
 {
 linked.push(linkval);
 linkval = "";
 }
 } 
 }
 }
 //Option #3
 else if(num == 3)
 {
 //Pops linkedstack and prints all equations till linkedstack is null
 while(!allEqu.isEmptyStack())
 {
 System.out.println(allEqu.peek());
 allEqu.pop();
 }
 }
 else if(num == 4)
 {
 //While loop to pop stack and print all conversions
 while(!linked.isEmptyStack())
 {
 System.out.println(linked.peek());
 linked.pop();
 }
 }
 //Error checking
 else
 {
 System.out.println("Invalid number. Enter number between 1 and 4");
 System.exit(0);
 }
 }
 } 
}