I have never used octal numbers in my code nor come across any code that used it. I bet you have. According to the standard, numeric literals which start with zero are octal. This includes, trivially, 0. Every time you have used or seen a literal zero, this has been octal. Strange but true.
If you are making child support payments in Texas, the law generally requires you to do so until your child turns 18, which is the age that marks adulthood in the state, or when he graduates from high school -- whichever comes later.
Child support terminates when a child turns 18 years old except when the 18-year-old child is still a full-time high school student and lives with a parent. In that situation, child support terminates when the child turns 19 or graduates from high school, whichever occurs first.