Organize related data into structures (`struct`s or `class`es)

Reason

Ease of comprehension. If data is related (for fundamental reasons), that fact should be reflected in code.

Example

void draw(int x, int y, int x2, int y2);  // BAD: unnecessary implicit relationships
void draw(Point from, Point to);          // better

Note

A simple class without virtual functions implies no space or time overhead.

Note

From a language perspective class and struct differ only in the default visibility of their members.

Enforcement

Probably impossible. Maybe a heuristic looking for data items used together is possible.