From 57a49cae35457a9c71e1322cbf6cb2d341713dfc Mon Sep 17 00:00:00 2001
From: Peter Vanhoef <petervanhoef@MacBook-Pro-van-Peter.local>
Date: Sun, 26 Mar 2017 22:41:31 +0200
Subject: [PATCH] Completes extra credit 1 and closes #12

---
 Calculator/Calculator/Base.lproj/Main.storyboard |  2 +-
 Calculator/Calculator/ViewController.swift       | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/Calculator/Calculator/Base.lproj/Main.storyboard b/Calculator/Calculator/Base.lproj/Main.storyboard
index 113799c..a20ba7b 100644
--- a/Calculator/Calculator/Base.lproj/Main.storyboard
+++ b/Calculator/Calculator/Base.lproj/Main.storyboard
@@ -51,7 +51,7 @@
                                                         <fontDescription key="fontDescription" type="system" pointSize="30"/>
                                                         <state key="normal" title="BS"/>
                                                         <connections>
-                                                            <action selector="clear:" destination="BYZ-38-t0r" eventType="touchUpInside" id="qr1-Ca-0eX"/>
+                                                            <action selector="backspace:" destination="BYZ-38-t0r" eventType="touchUpInside" id="Klu-Xx-Mpz"/>
                                                         </connections>
                                                     </button>
                                                     <button opaque="NO" contentMode="scaleToFill" contentHorizontalAlignment="center" contentVerticalAlignment="center" buttonType="roundedRect" lineBreakMode="middleTruncation" translatesAutoresizingMaskIntoConstraints="NO" id="NCt-oF-aVp">
diff --git a/Calculator/Calculator/ViewController.swift b/Calculator/Calculator/ViewController.swift
index 3f80ae9..3e4a7cd 100644
--- a/Calculator/Calculator/ViewController.swift
+++ b/Calculator/Calculator/ViewController.swift
@@ -60,5 +60,17 @@ class ViewController: UIViewController {
         displayValue = 0
         sequence.text = " "
     }
+    
+    @IBAction func backspace(_ sender: UIButton) {
+        if userIsInTheMiddleOfTyping {
+            var textCurrentlyInDisplay = display.text!
+            textCurrentlyInDisplay.remove(at: textCurrentlyInDisplay.index(before: textCurrentlyInDisplay.endIndex))
+            if textCurrentlyInDisplay.isEmpty {
+                userIsInTheMiddleOfTyping = false
+                textCurrentlyInDisplay = "0"
+            }
+            display.text = textCurrentlyInDisplay
+        }
+    }
 }