There is lot of difference between Structural engineer and Architect as both play integral part in civil engineering. Architect is the first person to plan the building as per the owners requirements. Then comes structural engineer who arranges the position of Beams, columns and other structural elements from design point of view.
Role of Civil Engineer and Architect
Though there are differences in their respective duties , both form very crucial in executing a civil engineering project successfully. Specially, an architect should never take decisions regarding the structural aspect or strength aspects of the building. See here for some basics of structural engineering.