""" Output: Enter a Postfix Equation (space separated) = 5 6 9 * + Symbol | Action | Stack ----------------------------------- 5 | push(5) | 5 6 | push(6) | 5,6 9 | push(9) | 5,6,9 | pop(9) | 5,6 | pop(6) | 5 * | push(6*9) | 5,54 | pop(54) | 5 | pop(5) | + | push(5+54) | 59 Result = 59 """ import operator as op def Solve(Postfix): Stack = [] Div = lambda x, y: int(x/y) # integer division operation Opr = {'^':op.pow, '*':op.mul, '/':Div, '+':op.add, '-':op.sub} # operators & their respective operation # print table header print('Symbol'.center(8), 'Action'.center(12), 'Stack', sep = " | ") print('-'*(30+len(Postfix))) for x in Postfix: if( x.isdigit() ): # if x in digit Stack.append(x) # append x to stack print(x.rjust(8), ('push('+x+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format else: B = Stack.pop() # pop stack print("".rjust(8), ('pop('+B+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format A = Stack.pop() # pop stack print("".rjust(8), ('pop('+A+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format Stack.append( str(Opr[x](int(A), int(B))) ) # evaluate the 2 values poped from stack & push result to stack print(x.rjust(8), ('push('+A+x+B+')').ljust(12), ','.join(Stack), sep = " | ") # output in tabular format return int(Stack[0]) if __name__ == "__main__": Postfix = input("\n\nEnter a Postfix Equation (space separated) = ").split(' ') print("\n\tResult = ", Solve(Postfix))