What is dangling else problem and why does this appear here

What is dangling else problem and why does this appear here

Describe the \"dangling else problem\". That is, describe why the code fragment below can have different meanings and why this problem is caused by the grammar. if C1 then if C2 then S1 else S2

Solution

Dangling else : The phenomenon of having to pick between one of two possible if conditions

Given grammar can be written in following ways.

if C1
   if C2
       S1
   else
       S2
In above snippet, else is there for second if condition
      
if C1
   if C2
       S1
else
   S2
In above snippet, else it there for first if condition

We have 2 different possibilities for the grammar given.
  
This Dangling Else problem is cause because of not using