What ways do you know for converting objects into a byte sequence or other format for transmission or storage?

Object serialization into a byte sequence or another format for transmission or storage is called serialization. In C/C++, several methods are used for this:

• Manual serialization: independently writing the fields of a structure or class into a buffer, considering alignment and byte order.
• Using standard functions: for example, memcpy for copying data into a byte array.
• Binary formats: such as Protocol Buffers, FlatBuffers, which provide convenient APIs for serialization and deserialization.
• Text formats: JSON, XML — converting an object into a string representation.

An example of simple manual serialization of a structure in C++:

struct Point {
    int x;
    int y;
};

void serialize(const Point& p, char* buffer) {
    memcpy(buffer, &p.x, sizeof(int));
    memcpy(buffer + sizeof(int), &p.y, sizeof(int));
}

void deserialize(const char* buffer, Point& p) {
    memcpy(&p.x, buffer, sizeof(int));
    memcpy(&p.y, buffer + sizeof(int), sizeof(int));
}

It is important to consider byte order (endianness) and alignment when transmitting between different systems.