Question

Using Java- Write a program that takes an arithmetic expression in an infix form, converts it to a postfix form and then evaluates it. Use linked lists for the infix and postfix queues and the operator and value stacks. You must use sperate Stack and Queue classes with a driver class to run the program.

example Input : 111++

Output : (1+ (1+ 1))

Answer: 3

Answer 1

import java.util.Stack;

import java.util.Iterator;
import java.util.List;
import java.util.Scanner;
public class B1Work {

   public static boolean precedence(char first, char second) {

       if (second == '(' || second == ')')
           return false;
       if ((first == '*' || first == '/') && (second == '+' || second == '-'))
           return false;
       else
           return true;

   }
  
   public static java.awt.Point highestPoint( List<java.awt.Point> points){
       Iterator < java.awt.Point> pointIterator = points.iterator();
      
       java.awt.Point highestPoint = null;
      
       while(pointIterator.hasNext()) {
           java.awt.Point p = pointIterator.next();
           if(highestPoint == null)
               highestPoint = p;
           else if(highestPoint != null && p.getY() > highestPoint.getY() )
               highestPoint = p;
       }
      
      
       return highestPoint;

   }
  
  
public class Outer{
   int data = 5;
   public void displayString() {
       class InnerClass1{
           int data2 = 10;
           public String getString() {
               return "Outer:" + data + ", Inner:" + data2;
           }
          
       }
      
       InnerClass1 ic = new InnerClass1();
       System.out.println(ic.getString());
      
   }
  
  
   int allEvenBits(int x) {
      
      
       int mask = 0xAAAAAAAA;
      
       int ans = x | mask ;
      
       return ~ans;
   }
   void Test(){
       displayString();
   }
  
  
  
  
}
public static String infixToPostfix(String infix) {
/*
* Convert an infix math formula to postfix format
* Infix format will always include parens around any two values and a symbol
* You will not need to imply any PEMDAS rules besides parens
* EXAMPLES:
* infix: (1+2) postfix: 12+
* infix: (1+(2-3)) postfix: 123-+
* infix: ((1+2)-3) postfix: 12+3-
* infix: ((1+2)-(3*4)) postfix: 12+34*-
*/
   char character[] = infix.toCharArray();
       Stack<Character> st = new Stack<Character>();
       for (int i = 0; i < character.length; i++) {
           if (character[i] == '(')
               st.push(character[i]);
           if (character[i] == ')') {

               if (st.isEmpty()) {
                   return "No matching open parenthesis error";
               }
               st.pop();

           }

       }

       if (!st.isEmpty())
           return "No matching close parenthesis error";

       // initialize the resulting postfix string
       String postfixString = "";

       // initialize the stack
       Stack<Character> stack1 = new Stack<Character>();

       // Obtain the character at index i in the string
       for (int i = 0; i < infix.length(); i++) {
           char ch = infix.charAt(i);

           if (Character.isLetter(ch) || Character.isDigit(ch))

               postfixString = postfixString + ch;

           else if (ch == '(') {

               stack1.push(ch);

           } else if (ch == ')') {

               while (stack1.peek() != '(') {

                   postfixString = postfixString + stack1.pop();

               }

               stack1.pop();

           } else {

               while (!stack1.isEmpty() && !(stack1.peek() == '(') && precedence(ch, stack1.peek()))

                   postfixString = postfixString + stack1.pop();

               stack1.push(ch);

           }

       }

       while (!stack1.isEmpty())

           postfixString = postfixString + stack1.pop();

       return postfixString;
}


public static boolean isCharacter(char ch) {
return (ch >= 'a' && ch <= 'z') ||
(ch >= 'A' && ch <= 'Z') || Character.isDigit(ch);
}
public static String postfixToInfix(String postfix) {
/*
* Convert a postfix math formula to an infix format
* See above for conversion examples
* Make sure to include parens in the infix format
*
*
*/
     
     
   Stack<String> stack = new Stack<String>();
     
   for (int i = 0; i < postfix.length(); i++)
   {
   if (isCharacter(postfix.charAt(i)))
       stack.push(postfix.charAt(i) + "");
   else
   {
   String operator1 = stack.peek();
   stack.pop();
   String operator2 = stack.peek();
   stack.pop();
   stack.push("(" + operator2 + postfix.charAt(i) +
           operator1 + ")");
   }
   }
   return stack.peek();
}

public static double solvePostfix(String s) {
// Stack<Integer> stack = new Stack<>();
/*
* Use a Stack to help solve a postfix format formula for the numeric answer
* Order of operations is implied by where symbols/numbers exist
* EXAMPLES
* postfix: 12+ = 3
* postfix: 123-+ = 0 :: 2-3 = -1 :: 1 + (-1) = 0
*/
  
Stack<Double> postfix = new Stack<Double>();
       for (int i = 0; i < s.length(); i++) {
           char c = s.charAt(i);

           if (Character.isDigit(c))
               postfix.push((double) (c - '0'));
           else {
               double val1 = postfix.peek();
               postfix.pop();
               double val2 = postfix.peek();
               postfix.pop();

               switch (c) {
               case '+':
                   postfix.push(val2 + val1);
                   break;

               case '-':
                   postfix.push(val2 - val1);
                   break;

               case '/':
                   postfix.push(val2 / val1);
                   break;

               case '*':
                   postfix.push(val2 * val1);
                   break;
               }
           }
       }
       return postfix.peek();
}

}

//--------------------------------------------------------------------

public class B1Driver {

public static void main(String[] args) {
     
     
Scanner s = new Scanner(System.in);
String format = "";
do {
System.out.print("What format will your formula be in (infix/postfix):");
format = s.nextLine().toLowerCase();
}while(!(format.equals("infix") || format.equals("postfix")));
System.out.print("Enter your formula:");
String formula = s.nextLine().replaceAll(" ", "");//removes whitespace
String infix, postfix;
switch(format) {
case "infix":
infix = formula;
postfix = B1Work.infixToPostfix(infix);
System.out.println("Infix:"+infix);
System.out.println("Postfix:"+postfix);
System.out.println("Answer:"+B1Work.solvePostfix(postfix));
break;
case "postfix":
postfix = formula;
infix = B1Work.postfixToInfix(postfix);
System.out.println("Infix:"+infix);
System.out.println("Postfix:"+postfix);
System.out.println("Answer:"+B1Work.solvePostfix(postfix));
break;
}
}

}

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SEE OUTPUT

254 255 248 public class B1Driver { 249 250 public static void main(String[] args) { 251 252 0.253 Scanner s = new Scanner(System.in); String format = ""; do { 256 System.out.print("What format will your formula be in (infix/postfix):"); 257 format = s.nextLine().toLowerCase(); } while(!(format.equals("infix") || format.equals("postfix")); 259 System.out.print("Enter your formula:"); String formula = s.nextLine().replaceAll(" ", "");//removes whitespace 261 String infix, postfix; 262 switch(format) { 263 case "infix": 264 infix = formula; postfix = B1 Work.infixToPostfix(infix); 258 260 265 Console X <terminated> B1 Driver [Java Application] /Library/Java/JavaVirtual Machines/jdk1.8.0_202.jdk/Contents/Home/bin/java (16-Oct What format will your formula be in (infix/postfix): postfix Enter your formula:111++ Infix:(1+(1+1) Postfix:111++ Answer:3.0

Thanks, PLEASE COMMENT if there is any concern.