Four4Sample - NaN propagation for number + string eval

brian-dot-net · Mar 11, 2018 · 5be66b9 · 5be66b9
1 parent d64418b
commit 5be66b9
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Showing 2 changed files with 15 additions and 7 deletions.
diff --git a/projects/Four4Sample/Four4.Test/CalculatorTest.cs b/projects/Four4Sample/Four4.Test/CalculatorTest.cs
@@ -137,6 +137,7 @@ public void SquareRoot(string input, string result)
         [InlineData(1, 2, "4 +", "9/2")]
         [InlineData(3, 4, "4 -", "-13/4")]
         [InlineData(0, 1, "!", "1")]
+        [InlineData(0, 0, "!", "NaN")]
         public void EvalNumberAndString(int num, int denom, string input, string result)
         {
             TestEval(num, denom, input, result);

diff --git a/projects/Four4Sample/Four4/Number.cs b/projects/Four4Sample/Four4/Number.cs
@@ -15,14 +15,21 @@ public struct Number
 
         public Number(int num, int denom)
         {
-            int gcd = Gcd(num, denom);
-            this.num = num / gcd;
-            this.denom = denom / gcd;
-
-            if (this.denom < 0)
+            if (denom == 0)
+            {
+                this = NaN;
+            }
+            else
             {
-                this.num *= -1;
-                this.denom *= -1;
+                int gcd = Gcd(num, denom);
+                this.num = num / gcd;
+                this.denom = denom / gcd;
+
+                if (this.denom < 0)
+                {
+                    this.num *= -1;
+                    this.denom *= -1;
+                }
             }
         }