Handle nil shape in PrintProperties method

Author: 0xSangeet

challenge-10/submissions/0xSangeet/solution-template.go

@@ -97,6 +97,10 @@ func NewShapeCalculator() *ShapeCalculator {
 
 // PrintProperties prints the properties of a shape
 func (sc *ShapeCalculator) PrintProperties(s Shape) {
+	if s == nil {
+		fmt.Println("<nil>")
+		return
+	}
 	fmt.Println(s.String())
 }
 
@@ -140,4 +144,4 @@ func (sc *ShapeCalculator) SortByArea(shapes []Shape, ascending bool) []Shape {
         return sorted[i].Area() > sorted[j].Area()
     })
     return sorted
-} 
+}