A framework hinged to a wall has no symmetry in general. Each force must be calculated individually. To find the tension or compression is each rod for the framework shown below, start by assuming each rod is in tension, so each rod will have a force directed towards its centre.

Resolve vertically at C.

Resolve horizontally at C.

The minus here means the rod BC is in compression.

Resolve vertically at B.

Resolve horizontally at B.