When debugging the runtime library, where is the source code of the runtime library?

辉煌魔剑弑神

E.g:
The element new operator in the debug runtime is to want to trace to the source code of new,
I read some books that the source code of new is in new.cpp.
Don't know where new.cpp is?

mfc library is source code
But the C ++ runtime does not know if there is any source code?

hamnhamn3

F5 Debug tracking

pretendersam

MFC in afxmem.cpp

辉煌魔剑弑神

Thank you Xiaoyao brother