Which kind of DC-DC Converter is this?

DC circuit with two horizontal rails and input U_E on the left, output U_A on the right. A switch S is inserted in the upper input rail. Immediately after S, an inductor L connects vertically from the upper node to the lower common rail, with a ground symbol at its lower end. A diode D is in series in the upper rail between this node and the output, with its cathode bar on the left. A capacitor C connects vertically across the output rails. The polarity markings show input + above/− below and output − above/+ below, with both voltage arrows pointing downward.