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.
Generally, the law in New Hampshire is that child support ends when the child turns 18 or graduates from high school, whichever is later. Yet, the answer to the question is not that simple. Sometimes, there may be a circumstance which can extend child support, for example if your child is disabled.