For some force majeure and historical reasons, we had to use some C code (even old C code) in C++, for example, Linux system calls. Before the advent of modern C++, most people talked about "what is the difference between C and C++". Generally speaking, in addition to answering the object-oriented class features and the template features of generic programming, there is no other opinion, or even a direct answer. "Almost" is also a lot of people. TheWayne diagram in Figure 1.2 roughly answers the C and C++ related compatibility.

For some force majeure and historical reasons, we had to use some C code (even old C code) in C++, for example, Linux system calls. Before the advent of modern C++, most people talked about "what is the difference between C and C++". Generally speaking, in addition to answering the object-oriented class features and the template features of generic programming, there is no other opinion, or even a direct answer. "Almost" is also a lot of people. TheVenn diagram in Figure 1.2 roughly answers the C and C++ related compatibility.