Why do we use double o or double 1 instead of spelling the letter twice (11 or oo) ?

if we will say 00 we say it double o not oo and also c++ is c double plus so why is it used that way

Why do we use double o or double 1 instead of spelling the letter twice (11 or oo) ?
I believe this is purely an idiomatic thing.





Sometimes, depending on context, location and usage of English by the speaker, one person will say "zero zero", while other person, for exactly the same thing (like a phone number, which is made of numbers only) will say "ou ou" when talking about zeroes.





Now, C++ (C plus plus) is purely idiomatic. If at the beginning it would have been called "C double plus", then everybody would say it that way now; but, as everything idiomatic in English, from the very beginning the name was coined as C plus plus, probably by the creators of the language, and it kept that way, as an idiomatic pronunciation, as opposed to a rational or logical one.





The English language, grammatically speaking, is full of unresolved "whys", justified always by the same explanation/justification: "It's idiomatic usage".
Reply:Because there is another word for 11, and that's eleven. There is no other word for 00 or c++.