The electronic structure and heat capacity of quantum wires and dots are studied in strong magnetic fields. For a quantum dot structure we consider a spheroidal shape with 2 electrons including Coulomb interactions. The calculated heat capacity exhibits oscillating behavior and is zero at the magnetic field where the angular momentum of the ground state changes discontinuously. For a quantum wire structure, the density of states is sawtooth-like. The oscillating pattern of heat capacity consists of several sets of asymmetric double peaks which arise whenever the chemical potential (mu) passes through a quantized energy level. These doublet features are resulted from the fact that the thermal excitation of electrons becomes largest when mu lies near a quantized energy level, but not at the level.