How to use a variable in format statement in Fortran?

[manugv]

hello everyone!
I was do programming in fortran and i wanted to print my answer in the format below. I was not able to do it. I have written a part of my program also.
i.e,
##$# greeting = 'Good Morning!' do 110 I = 1, 12 write (*,115) (greeting) 115 format (A<I>) 110 continue end$###
here i want to use a variable 'I' in the format statement i tried it doing but i failed. so please if anyone knows to use a variable in format statement tell me.
I use gcc-3.4.6 compiler.

output of the program
G
Go
Goo
Good
Good
Good M
Good Mo
Good Mor
Good Morn
Good Morni
Good Mornin
Good Morning

 

[DrClaude]

Variable format specifiers are not part of the standard and not supported by gcc. See
https://gcc.gnu.org/onlinedocs/gcc-4.7.2/gfortran/Variable-FORMAT-expressions.html