public static void main(String[] args) { Calculation calculation = new Calculation(); System.out.println("-------------------------------"); System.out.print(" Enter the argument:"); Double x = getArgumentFromConsole(); int i = 0; while (true) { System.out.print(" Enter the operation:"); String operation = getOperationFromConsole(); if (!(operation.equals("+") || operation.equals("-") || operation.equals("*") || operation.equals("/"))) { if (i == 0) { calculation.setTotal(x); calculation.calculate(operation); i++; } else { calculation.calculate(operation); i++; } } else { System.out.print(" Enter the argument:"); Double y = getArgumentFromConsole(); if (i == 0) { calculation.calculate(x, y, operation); } else { calculation.calculate(y, operation); } i++; } System.out.println("-------------------------------"); System.out.println("Result:" + calculation.getTotal()); System.out.println(); System.out.println(); } }