whats real use of veriable in application? with example

Answer 1

Simple: they hold data.

Things that make them more complex:
1. access modifiers, which specifies where you can use a variable. Sometimes called variable scope.
2. functions, combine functions and variables and you have the basics of a lot of languages (and classes maybe). Variabels will hold your data within the program until they are out of scope or you stop the program.

Functions let you operate on that data, so you can change the data your program holds in that way.

That said: with this it is possible to retrieve text from a source and store it in a variable in the program. When we change the content of the variable with a function and then store the variable in the source, we have changed the content of a source file.

Awesome!

Hope this makes things clear for you :)

Answer 2

Rohit Chavda if you would like you can mark my answer as best :)

Answer 3

thanks thats help : D