calculator.js Example File

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  **
  ** Copyright (C) 2015 The Qt Company Ltd.
  ** Contact: http://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** You may use this file under the terms of the BSD license as follows:
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  ** modification, are permitted provided that the following conditions are
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  **     from this software without specific prior written permission.
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  var curVal = 0
  var memory = 0
  var lastOp = ""
  var previousOperator = ""
  var digits = ""

  function disabled(op) {
      if (digits == "" && !((op >= "0" && op <= "9") || op == "."))
          return true
      else if (op == '=' && previousOperator.length != 1)
          return true
      else if (op == "." && digits.toString().search(/\./) != -1) {
          return true
      } else if (op == "√" &&  digits.toString().search(/-/) != -1) {
          return true
      } else {
          return false
      }
  }

  function digitPressed(op)
  {
      if (disabled(op))
          return
      if (digits.toString().length >= display.maxDigits)
          return
      if (lastOp.toString().length == 1 && ((lastOp >= "0" && lastOp <= "9") || lastOp == ".") ) {
          digits = digits + op.toString()
          display.appendDigit(op.toString())
      } else {
          digits = op
          display.appendDigit(op.toString())
      }
      lastOp = op
  }

  function operatorPressed(op)
  {
      if (disabled(op))
          return
      lastOp = op

      if (op == "±") {
              digits = Number(digits.valueOf() * -1)
              display.setDigit(display.displayNumber(digits))
              return
          }

      if (previousOperator == "+") {
          digits = Number(digits.valueOf()) + Number(curVal.valueOf())
      } else if (previousOperator == "−") {
          digits = Number(curVal.valueOf()) - Number(digits.valueOf())
      } else if (previousOperator == "×") {
          digits = Number(curVal) * Number(digits.valueOf())
      } else if (previousOperator == "÷") {
          digits = Number(curVal) / Number(digits.valueOf())
      }

      if (op == "+" || op == "−" || op == "×" || op == "÷") {
          previousOperator = op
          curVal = digits.valueOf()
          digits = ""
          display.displayOperator(previousOperator)
          return
      }

      if (op == "=") {
          display.newLine("=", digits.valueOf())
      }

      curVal = 0
      previousOperator = ""

      if (op == "1/x") {
          digits = (1 / digits.valueOf()).toString()
      } else if (op == "x^2") {
          digits = (digits.valueOf() * digits.valueOf()).toString()
      } else if (op == "Abs") {
          digits = (Math.abs(digits.valueOf())).toString()
      } else if (op == "Int") {
          digits = (Math.floor(digits.valueOf())).toString()
      } else if (op == "√") {
          digits = Number(Math.sqrt(digits.valueOf()))
          display.newLine("√", digits.valueOf())
      } else if (op == "mc") {
          memory = 0;
      } else if (op == "m+") {
          memory += digits.valueOf()
      } else if (op == "mr") {
          digits = memory.toString()
      } else if (op == "m-") {
          memory = digits.valueOf()
      } else if (op == "backspace") {
          digits = digits.toString().slice(0, -1)
          display.clear()
          display.appendDigit(digits)
      } else if (op == "Off") {
          Qt.quit();
      }

      // Reset the state on 'C' operator or after
      // an error occurred
      if (op == "C" || display.isError) {
          display.clear()
          curVal = 0
          memory = 0
          lastOp = ""
          digits = ""
      }
  }