void function ( int arg0 ) { }
task 5b : calculator history - print history helper methods printhistory prints each equation and its corresponding result , most recent equation first with one equation per line . a maximum of n equations should be printed out . please print in the following format : ex `` 1 + 2 = 3 '' concode_field_sep PlaceHolder placeHolder concode_field_sep int add concode_elem_sep void printAllHistory concode_elem_sep void clearHistory concode_elem_sep int cumulativeSum concode_elem_sep void undoEquation concode_elem_sep int multiply concode_elem_sep void saveEquation concode_elem_sep int cumulativeProduct