Answer 1

Manav Roy
The second parameter in s.substring is the number of characters, not the end index.
try this:
s=s.substr(i1+1,i2-i1-1);

Answer 2

The 2nd argument of the substr method is not the end index but the span (how many characters from the starting point)

s=s.substr(i1+1,i2-i1-1);

Answer 3

Manav Roy
You probably would have to mess around with regex sooner or later. It is a pain to get right.

https://code.sololearn.com/cGnWsbs8BvB8/?ref=app