calculator

calcu.py

 n1=int(input("enter the first number"))
 n2=int(input("enter the second number"))
+
 print("\n")
 def add(n1,n2):
     return n1+n2
@@ -8,6 +9,8 @@ def sub(n1,n2):
 def mul(n1,n2):
     return n1*n2
 def div(n1,n2):
+    if n2==0:
+        print("not defined")
     return n1/n2
 print("sum=",add(n1,n2))
 print("sub=",sub(n1,n2))