Fix factorial of 0

closes #186
sadellie · Feb 11, 2024 · ebb5fc5 · ebb5fc5
1 parent 5a7fd41
commit ebb5fc5
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diff --git a/data/evaluatto/src/main/java/io/github/sadellie/evaluatto/BigDecimalMath.kt b/data/evaluatto/src/main/java/io/github/sadellie/evaluatto/BigDecimalMath.kt
@@ -93,6 +93,8 @@ internal fun BigDecimal.factorial(): BigDecimal {
     if (this < BigDecimal.ZERO) throw ExpressionException.FactorialCalculation()
     if (this > maxFactorial) throw ExpressionException.TooBig()
 
+    if (this.compareTo(BigDecimal.ZERO) == 0) return BigDecimal.ONE
+
     var expr = this
     for (i in 1 until this.toInt()) {
         expr *= BigDecimal(i)

diff --git a/data/evaluatto/src/test/java/io/github/sadellie/evaluatto/ExpressionSimpleTest.kt b/data/evaluatto/src/test/java/io/github/sadellie/evaluatto/ExpressionSimpleTest.kt
@@ -108,4 +108,7 @@ class ExpressionSimpleTest {
 
     @Test
     fun expression28() = assertExpr("e", "2.7182818285")
+
+    @Test
+    fun expression29() = assertExpr("0!", "1")
 }
-Original file line number
+Diff line change
@@ Expand Up / @@ -108,4 +108,7 @@ class ExpressionSimpleTest { @@
         @Test
         fun expression28() = assertExpr("e", "2.7182818285")
+        @Test
+        fun expression29() = assertExpr("0!", "1")
     }