iPhone计算器输入时小数位反转

Question

在做教程工作时，我花了很长时间才实现小数点，现在我有了一个可以在公式中使用的小数点，但问题是它反转了输入 - 例如输入 1.4，计算器屏幕将其显示为4.1 - 我知道它与我对变量的管理有关..计划使用 BOOL 而不是 float ..但是..有接受者吗？

代码:

     - (IBAction) pressedDecimal: (id) sender
     {
       pressedDec = 1;
     }

    - (IBAction) pressedDigit: (id) sender 
     {
       if (pressedDec == 1) 
       {currentNumber = .1 * currentNumber + (double)[sender tag];
       calculatorScreen.text = [NSString stringWithFormat:@"%g",currentNumber];
      }
else

     {

       currentNumber =  currentNumber * 10 + (double)[sender tag];
       calculatorScreen.text = [NSString stringWithFormat:@"%g",currentNumber];
       pressedDec = 0;

      }
     }



  - (IBAction) pressedOperation: (id) sender 
   {
if (currentOperation == 0) result = currentNumber;
else {
    switch (currentOperation) {
        case 1:
            result = result + currentNumber;
            break;
        case 2:
            result = result - currentNumber;
            break;
        case 3:
            result = result * currentNumber;
            break;
        case 4:
            result = result / currentNumber;
            break;
        case 5:
            currentOperation = 0;
            break;


    }

}
currentNumber = 0;
calculatorScreen.text = [NSString stringWithFormat:@"%g",result];
if ([sender tag] == 0) result = 0;
currentOperation = [sender tag];
  }

Answer 1

更仔细地考虑代码中的这段摘录的作用:

currentNumber = .1 * currentNumber + (double)[sender tag];

(我不是很明确，因为如果我正确理解了这个问题，你这样做是为了学习，你思考得越多，你就会学得越好:-)。)