adding 1 to an integer within println statement in Java

Question

super beginner here, so please bear with me. I am writing this program to print Fibonacci series. What I want is the result to display the series with prefix like F0 = 0, F1 = 1, F2 = 1, F3 = 2 and so on.
Some others who faced this problem were not using parenthesis in the println statement, but I am using them, still getting a wrong display.

I wrote the following program:

public void run () {
int firstNo = 0;

int secondNo = 1;

int n = 0;

println ("F"+(n)+ "= " + firstNo );// FIRST LINE

println ("F" +(n++)+ "= " + secondNo);// SECOND LINE

for (int i =0; i <7; i++) {
firstNo += secondNo;
println ("F"+(n++)+ "= " + firstNo );
secondNo +=firstNo;
println ("F" + (n++) + "= " + secondNo);
}}

The display I am getting is F0 = 0, F0 = 1, F1 = 1, F2 = 2 and so on

However if I cahnge the SECOND LINE from n++ to n=n+1 the display I get is F0 = 0, F1 = 1, F1 = 1, F2 = 2 etc

Q1 : Why am I not able to get the suffix of F in sequence? Am I doing something wrong in adding 1 to integer n within the println statement?

Q2 : Isn't n++ the same as n = n+1? Then why am I getting this difference in the display?