منذ فترة طويلة لقد بحثت عن ذلك السؤال ... المعظم لقد اجاب (سنتين) او (10 سنوات) ... لكن جميعها إجابات خاطئة (برأي) .

لكن عندما بحث في بالانكليزية لم اجد افضل من هذه الإجابات :

https://www.quora.com/How-much-time-is-required-to-learn-C-C++-and-Java

الإجابة الصحيحة برأي هي :

This is a very subjective question, as it depends (to a large extent) on what you mean by 'learn'.

It also depends on what other development experience you have.

The 'core basics' can be learnt fairly quickly (a few weeks) , particularly if you are familiar with programming concepts

It is then a question of what you want to do using C++, C and Java.

Honestly, I think if you want to learn any one of the above language from zero to advanced then you need at least 2–3 months and lots of practice…

So start Coding.