My output is same as input string

#1

https://ide.codingblocks.com/s/391923.Please check where i am going wrong.

#2

if(str.substring(0,2).equals(“pi”)){
in line 14

#3

so to compare string content we always should use equals ,is it?

#4

yes,
== tests for reference equality (whether they are the same object).

.equals() tests for value equality (whether they are logically “equal”).