I found this online to compare to our PEMDAS funciton.

Main.ctxt

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+#BlueJ class context
+comment0.target=Main
+comment1.params=input
+comment1.target=boolean\ pClose(java.lang.String)
+comment2.params=input\ num
+comment2.target=java.lang.Double\ calc(java.lang.String,\ int)
+comment3.params=args
+comment3.target=void\ main(java.lang.String[])
+numComments=4

Main.java

@@ -0,0 +1,83 @@
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.Scanner;
+import java.util.ArrayList;
+public class Main{
+    public static ArrayList<String> pemdas = new ArrayList<String>();
+    public static boolean pClose(String input){
+        int tracker = 0;
+        for(int i =0; i < input.length(); i++){
+            if(input.charAt(i) == '(') tracker++;
+            else if (input.charAt(i) == ')') tracker--;
+            if(tracker < 0) return false;
+        }
+        return tracker == 0; 
+    }
+
+    public static Double calc(String input, int num){ // p =0, e = 1, md = 2, as=3
+        //System.out.println(input);
+        Double result = null;
+        String next;
+        Pattern filter = Pattern.compile(pemdas.get(num));
+        Matcher calcMatch = filter.matcher(input);
+        if(!calcMatch.find()){
+            if(num < 3) return calc(input, num+1);
+            return null;
+        }
+        if(num == 0){
+            Double pSol = calc(calcMatch.group(2), 1);
+            if(pSol !=null){ result = pSol;
+                next = input.substring(0, calcMatch.start()) + result.toString() + input.substring(calcMatch.end());
+            }
+            else{
+                next = input.substring(0, calcMatch.start()) + input.substring(calcMatch.end());
+            }
+        }
+        else{
+            switch(calcMatch.group(2)){
+                case "+":
+                result = Double.parseDouble(calcMatch.group(1)) + Double.parseDouble(calcMatch.group(3));
+                break;
+                case "-":
+                result = Double.parseDouble(calcMatch.group(1)) - Double.parseDouble(calcMatch.group(3));
+                break;
+                case "/":
+                result = Double.parseDouble(calcMatch.group(1)) / Double.parseDouble(calcMatch.group(3));
+                break;
+                case "*":
+                result = Double.parseDouble(calcMatch.group(1)) * Double.parseDouble(calcMatch.group(3));
+                break;
+                case "^":
+                result = Math.pow(Double.parseDouble(calcMatch.group(1)), Double.parseDouble(calcMatch.group(3)));
+                break;
+                
+            }
+            next = input.substring(0, calcMatch.start()) + result.toString() + input.substring(calcMatch.end());
+        }
+        //for(int i = num; i <= 3; i++){
+        //if(calc(next,  i) != null) {return calc(next, i);}
+        //}
+        if(filter.matcher(next).find()) return calc(next, num);
+        if(num < 3){
+            Double nextResult = calc(next, num+1);
+            if(nextResult !=null) return nextResult;
+        }
+        return result;
+    }
+
+    public static void main(String args[]){
+        System.out.println("PEMDAS calculator! Just write an expression to solve how you normally would, like \"(2+3)*3\"! Supports + - * / ^ % as its operators. \"stop\" will stop the program.");
+        Scanner scanner = new Scanner(System.in);
+        String input;
+        pemdas.add("(\\()([^\\(\\)]*)(\\))");//detects anything in parenthesis
+        pemdas.add("(-?\\d+\\.?\\d*)\\D*?(\\^)\\D*?(-?\\d+\\.?\\d*)"); //exponents
+        pemdas.add("(-?\\d+\\.?\\d*)\\D*?(\\*|\\/|%)\\D*?(-?\\d+\\.?\\d*)"); //multiplication, division, 
+        pemdas.add("(-?\\d+\\.?\\d*)\\D*?(\\+|-)\\D*?(-?\\d+\\.?\\d*)"); // addition, subraction
+        while(true){
+            input = scanner.nextLine();
+            if(input.toLowerCase().equals("stop")) break; 
+            if(!pClose(input)) System.out.println("Error: There's a problem with your parenthesis, so the result may be different from what you expect.");
+            System.out.println(input + " is " + calc(input, 0));
+        }
+    }
+}