From: Ira W. Snyder <devel@irasnyder.com>
Date: Fri, 5 Oct 2007 18:26:17 +0000 (-0700)
Subject: Fix underflow in Position
X-Git-Url: https://irasnyder.com/gitweb/?a=commitdiff_plain;h=83a0692b324ab753ba9678b0d136a85fcca13930;p=cs356-p1-elevator.git

Fix underflow in Position

The operator-=() function in Position could underflow the part right of the
decimal point. Fix it.

Signed-off-by: Ira W. Snyder <devel@irasnyder.com>
---

diff --git a/position.cpp b/position.cpp
index f1cfc90..e0da0f4 100644
--- a/position.cpp
+++ b/position.cpp
@@ -44,7 +44,18 @@ Position& Position::operator+= (const float rhs)
 
 Position& Position::operator-= (const float rhs)
 {
-	*this += -rhs;
+	int major = (int)rhs;
+	int minor = (int)((rhs - major) * 10);
+
+	major_ -= major;
+	minor_ -= minor;
+
+	/* Check for underflow */
+	if (minor_ < 0)
+	{
+		major_ -= 1;
+		minor_ += 10;
+	}
 
 	return *this;
 }