How is the architecture of an application different from its algorithms?

Question

Programming

What comes first in development? Which is more flexible in terms of change?

Answer 1

The architecture is primary and usually it is quite problematic to change it in a finished application, unlike algorithms.

Answer 2

citforum.ru/programming/oop_rsis

Answer 3

Architecture is about what elements ("black boxes") a system / subsystem is assembled from.
Algorithms are about how the most low-level elements ("black boxes") and the functions they perform are implemented using a sequence of actions.
Architecture development involves partitioning a system into subsystems with well-defined responsibilities and relationships between them (and, in turn, subsystems into subsystems) until reaching the point where the responsibility of the subsystem can be represented using an algorithm that is simple enough for subsequent implementation in a programming language and further support for this implementation.
Accordingly, the architecture is primary. Algorithms with a well-built architecture should be easily changeable, because you are well aware of the responsibilities of a particular subsystem and how it affects other subsystems.
The exact definition of the algorithm can be found in other sources.