Electronic cash register

Abstract

An electronic cash register comprises a read only memory, a central processor unit, entry and function keys, memory means including an entry memory storing input data from said entry keys and first and second data memories storing respectively first and second data, a double function key for transferring first data to the first data memory and second data to the second data memory, and printing means for printing input data, price total and further the first and second data. The memory means further comprises a first flag memory storing a '1' when the entry memory stores the first data and a second flag memory storing a '1' when first data is transferred from the entry memory to the first data memory. When the double function key is operated while first data is stored in the entry memory and a '1' is stored only in the first flag memory, the first data is transferred to the first data memory and the second flag memory now stores a '1'. The entry and first flag memories are then cleared. Thereafter, when the double function key is operated while second data is stored in the entry memory and a '1' is stored in both the first and second flag memories, second data is transferred to the second data memory. If the transferred second data is incorrect, the entry keys are operated to store new correct second data into the entry memory. Then, the double function key is operated to transfer the new second data to the second data memory. Thereafter, the second flag memory is cleared to permit storing input data in the entry memory which represents a merchandise price.