What do You mean by inline function

Answer 1

It's a function marked with 'inline' keyword. Compiler can replace the call of such function by its body which will work faster. There are not many cases where you can get significant performance by inlining. Just let the compiler make a decision in 90% cases.

Answer 2

when the function itself is in the middle of main() codes it is called inline function. it is used for decreasing the time of execution as the compiler doesnt have to jump out of main code. Although it is useful to only one calling as it needs to be defined on each call itself.