From f9cda0832f065ec6a4fe1dd8539b908d03c08896 Mon Sep 17 00:00:00 2001
From: potatoes1286 <48143760+potatoes1286@users.noreply.github.com>
Date: Thu, 23 Mar 2023 11:27:09 -0400
Subject: [PATCH] Fix #196

Fixes #196 by preventing divide by percent calculations from being messed with, and adding brackets to fix order of operations
---
 .../com/darkempire78/opencalculator/Expression.kt     | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/app/src/main/java/com/darkempire78/opencalculator/Expression.kt b/app/src/main/java/com/darkempire78/opencalculator/Expression.kt
index 19385b65..81bc709a 100644
--- a/app/src/main/java/com/darkempire78/opencalculator/Expression.kt
+++ b/app/src/main/java/com/darkempire78/opencalculator/Expression.kt
@@ -55,6 +55,15 @@ class Expression {
         if (calculation[operatorBeforePercentPos] == '*') {
             return calculation
         }
+        
+        if(calculation[operatorBeforePercentPos] == '/') {
+            // insert brackets into percentage. Fixes 900/10% -> 900/(10/100), not 900/10/100 which evals differently.
+            // also prevents it from doing the rest of this function, which screws the calculation up
+            var stringFirst = calculation.substring(0, operatorBeforePercentPos+1)
+            var stringMiddle = calculation.substring(operatorBeforePercentPos+1, percentPos+1)
+            var stringLast = calculation.substring(percentPos+1, calculation.length)
+            return "$stringFirst($stringMiddle)$stringLast"
+        }
 
         // extract the first part of the calculation
         var calculationStringFirst = calculation.subSequence(0, operatorBeforePercentPos).toString()
@@ -279,4 +288,4 @@ class Expression {
     private fun String.addCharAtIndex(char: Char, index: Int) =
         StringBuilder(this).apply { insert(index, char) }.toString()
 
-}
\ No newline at end of file
+}