There is no 'printf'
This is a bit like saying there is no '+';Because if you put in    return 1+2+3;


And look at the assembly code, you will see that the compiler generated something like    return 6;


The compiler is allowed to take advantage of the standard to substitute in more efficient code that does the same thing.IIRC, for C++, it would actually be ok if std::vector was implemented completely as a compiler intrinsic with no actual header file. (No compiler I am aware of actually does it that way).