Thread: writing long double into ofstream file?

Dear All!

I defined a log double variable. That variable takes some values like :
long double varr = 0.038918918918916

i would like to write it to a file

Code:

long double varr = 0.038918918918916
ofstream out; 
out.open("ktr.txt");

out<< varr;

however, it writes as 0.389189. truncated.

How can I write it with originally in long format?

thank you