C:\>perl -le "print sqrt(3);"
1.73205080756888

C:\>perl -le "print 'WTF' if 1.73205080756888 != sqrt(3);"
WTF

##</code><code>##

C:\>perl -le "printf '%.16e', 1/100"
1.0000000000000000e-002
C:\>perl -le "printf '%.17e', 1/100"
1.00000000000000002e-002

##</code><code>##

C:\>perl -le "printf '%.16e', 0.1"
1.0000000000000001e-001