From d7caf1cdc73faa375c57c9ea0d3977b8d7f40714 Mon Sep 17 00:00:00 2001
From: Danila Fedorin <danila.fedorin@gmail.com>
Date: Wed, 26 Jul 2017 17:26:55 -0700
Subject: [PATCH] Implement toString in child nodes of TreeNode.

---
 src/org/nwapw/abacus/tree/NumberNode.java |  5 +++++
 src/org/nwapw/abacus/tree/OpNode.java     | 15 +++++++++++++++
 2 files changed, 20 insertions(+)

diff --git a/src/org/nwapw/abacus/tree/NumberNode.java b/src/org/nwapw/abacus/tree/NumberNode.java
index f88ef0a..41112e7 100644
--- a/src/org/nwapw/abacus/tree/NumberNode.java
+++ b/src/org/nwapw/abacus/tree/NumberNode.java
@@ -49,4 +49,9 @@ public class NumberNode extends TreeNode {
     public <T> T reduce(Reducer<T> reducer) {
         return reducer.reduceNode(this);
     }
+
+    @Override
+    public String toString() {
+        return number != null ? number.toString() : "null";
+    }
 }
diff --git a/src/org/nwapw/abacus/tree/OpNode.java b/src/org/nwapw/abacus/tree/OpNode.java
index 33ba805..8a399f7 100644
--- a/src/org/nwapw/abacus/tree/OpNode.java
+++ b/src/org/nwapw/abacus/tree/OpNode.java
@@ -88,4 +88,19 @@ public class OpNode extends TreeNode {
         T rightReduce = right.reduce(reducer);
         return reducer.reduceNode(this, leftReduce, rightReduce);
     }
+
+    @Override
+    public String toString() {
+        String leftString = left != null ? left.toString() : "null";
+        String rightString = right != null ? right.toString() : "null";
+
+        if(right != null && right instanceof OpNode){
+            if(TreeNode.precedenceMap.get(((OpNode) right).getOperation()) >
+                    TreeNode.precedenceMap.get(operation)) {
+                rightString = "(" + rightString + ")";
+            }
+        }
+        
+        return leftString + operation + rightString;
+    }
 }