calculator.js Example File | Qt 5.12

Qt 5.12 | Qt Quick Demo - Calqlatr | calculator.js Example File

Qt 5.12.5 Reference Documentation

# calculator.js Example File

demos/calqlatr/content/calculator.js

      /****************************************************************************
      **
      ** Copyright (C) 2017 The Qt Company Ltd.
      ** Contact: https://www.qt.io/licensing/
      **
      ** This file is part of the examples of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** Commercial License Usage
      ** Licensees holding valid commercial Qt licenses may use this file in
      ** accordance with the commercial license agreement provided with the
      ** Software or, alternatively, in accordance with the terms contained in
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      ** and conditions see https://www.qt.io/terms-conditions. For further
      ** information use the contact form at https://www.qt.io/contact-us.
      **
      ** BSD License Usage
      ** Alternatively, you may use this file under the terms of the BSD license
      ** as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
      ** met:
      **   * Redistributions of source code must retain the above copyright
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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 = ""
          }
      }