fix for float parsing of exactly 10.0

src/calc.rs

@@ -19,7 +19,7 @@ impl Display for StackCalcError {
         match self {
             StackCalcError::StackOverflow => f.write_str("stack overflow"),
             StackCalcError::StackUnderflow => f.write_str("stack underflow"),
-            StackCalcError::DecimalError(de) => de.fmt(f),
+            StackCalcError::DecimalError(de) => Display::fmt(de, f),
         }
     }
 }
@@ -185,4 +185,13 @@ mod tests {
         ));
         Ok(())
     }
+
+    #[test]
+    fn test_add_10() -> Result<(), StackCalcError> {
+        let mut calc = StackCalc::<f64, 3, 5>::default();
+        calc.push(Decimal::new(false, [3, 0, 0, 0, 0], false, 0))?;
+        calc.push(Decimal::new(false, [7, 0, 0, 0, 0], false, 0))?;
+        assert_eq!(calc.add()?, Decimal::new(false, [1, 0, 0, 0, 0], false, 1));
+        Ok(())
+    }
 }