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Using Bigdecimal for calculations ensures that precision is not lost. It can solve problems such as 0.1+0.2=0.300000000000000004
// src/main/com/houarizegai/calculator/ui/CalculatorUI.java
// src/main/com/houarizegai/calculator/ui/CalculatorUI.java package com.houarizegai.calculator.ui; import com.houarizegai.calculator.theme.properties.Theme; import com.houarizegai.calculator.theme.ThemeLoader; import java.awt.Cursor; import java.awt.Font; import java.awt.event.ItemEvent; import java.math.BigDecimal; import java.math.RoundingMode; import java.util.Map; import java.util.regex.Pattern; import java.awt.Color; import javax.swing.*; import static com.houarizegai.calculator.util.ColorUtil.hex2Color; public class CalculatorUI { private static final String FONT_NAME = "Comic Sans MS"; private static final String DOUBLE_OR_NUMBER_REGEX = "([-]?\\d+[.]\\d*)|(\\d+)|(-\\d+)"; private static final String APPLICATION_TITLE = "Calculator"; private static final int WINDOW_WIDTH = 410; private static final int WINDOW_HEIGHT = 600; private static final int BUTTON_WIDTH = 80; private static final int BUTTON_HEIGHT = 70; private static final int MARGIN_X = 20; private static final int MARGIN_Y = 60; private final JFrame window; private JComboBox<String> comboCalculatorType; private JComboBox<String> comboTheme; private JTextField inputScreen; private JButton btnC; private JButton btnBack; private JButton btnMod; private JButton btnDiv; private JButton btnMul; private JButton btnSub; private JButton btnAdd; private JButton btn0; private JButton btn1; private JButton btn2; private JButton btn3; private JButton btn4; private JButton btn5; private JButton btn6; private JButton btn7; private JButton btn8; private JButton btn9; private JButton btnPoint; private JButton btnEqual; private JButton btnRoot; private JButton btnPower; private JButton btnLog; private char selectedOperator = ' '; private boolean go = true; // For calculate with Opt != (=) private boolean addToDisplay = true; // Connect numbers in display private BigDecimal typedValue = BigDecimal.ZERO; private final Map<String, Theme> themesMap; public CalculatorUI() { themesMap = ThemeLoader.loadThemes(); window = new JFrame(APPLICATION_TITLE); window.setSize(WINDOW_WIDTH, WINDOW_HEIGHT); window.setLocationRelativeTo(null); int[] columns = {MARGIN_X, MARGIN_X + 90, MARGIN_X + 90 * 2, MARGIN_X + 90 * 3, MARGIN_X + 90 * 4}; int[] rows = {MARGIN_Y, MARGIN_Y + 100, MARGIN_Y + 100 + 80, MARGIN_Y + 100 + 80 * 2, MARGIN_Y + 100 + 80 * 3, MARGIN_Y + 100 + 80 * 4}; initInputScreen(columns, rows); initButtons(columns, rows); initCalculatorTypeSelector(); initThemeSelector(); window.setLayout(null); window.setResizable(false); window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); window.setVisible(true); } public BigDecimal calculate(BigDecimal firstNumber, BigDecimal secondNumber, char operator) { switch (operator) { case '+': return firstNumber.add(secondNumber).stripTrailingZeros(); case '-': return firstNumber.subtract(secondNumber).stripTrailingZeros(); case '*': return firstNumber.multiply(secondNumber).stripTrailingZeros(); case '/': return firstNumber.divide(secondNumber, 16, RoundingMode.HALF_UP).stripTrailingZeros(); case '%': return firstNumber.remainder(secondNumber).stripTrailingZeros(); case '^': double result=Math.pow(firstNumber.doubleValue(),secondNumber.doubleValue()); return new BigDecimal(result).setScale(16, RoundingMode.HALF_UP).stripTrailingZeros(); default: return secondNumber.stripTrailingZeros(); } } private void initThemeSelector() { comboTheme = createComboBox(themesMap.keySet().toArray(new String[0]), 230, 30, "Theme"); comboTheme.addItemListener(event -> { if (event.getStateChange() != ItemEvent.SELECTED) return; String selectedTheme = (String) event.getItem(); applyTheme(themesMap.get(selectedTheme)); }); if (themesMap.entrySet().iterator().hasNext()) { applyTheme(themesMap.entrySet().iterator().next().getValue()); } } private void initInputScreen(int[] columns, int[] rows) { inputScreen = new JTextField("0"); inputScreen.setBounds(columns[0], rows[0], 350, 70); inputScreen.setEditable(false); inputScreen.setBackground(Color.WHITE); inputScreen.setFont(new Font(FONT_NAME, Font.PLAIN, 33)); window.add(inputScreen); } private void initCalculatorTypeSelector() { comboCalculatorType = createComboBox(new String[]{"Standard", "Scientific"}, 20, 30, "Calculator type"); comboCalculatorType.addItemListener(event -> { if (event.getStateChange() != ItemEvent.SELECTED) return; String selectedItem = (String) event.getItem(); switch (selectedItem) { case "Standard": window.setSize(WINDOW_WIDTH, WINDOW_HEIGHT); btnRoot.setVisible(false); btnPower.setVisible(false); btnLog.setVisible(false); break; case "Scientific": window.setSize(WINDOW_WIDTH + 80, WINDOW_HEIGHT); btnRoot.setVisible(true); btnPower.setVisible(true); btnLog.setVisible(true); break; } }); } private void initButtons(int[] columns, int[] rows) { btnC = createButton("C", columns[0], rows[1]); btnC.addActionListener(event -> { inputScreen.setText("0"); selectedOperator = ' '; typedValue = BigDecimal.ZERO; }); btnBack = createButton("<-", columns[1], rows[1]); btnBack.addActionListener(event -> { String str = inputScreen.getText(); StringBuilder str2 = new StringBuilder(); for (int i = 0; i < (str.length() - 1); i++) { str2.append(str.charAt(i)); } if (str2.toString().equals("")) { inputScreen.setText("0"); } else { inputScreen.setText(str2.toString()); } }); btnMod = createButton("%", columns[2], rows[1]); btnMod.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText()) || !go) return; // typedValue = calculate(typedValue, Double.parseDouble(inputScreen.getText()), selectedOperator); typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '%'; go = false; addToDisplay = false; }); btnDiv = createButton("/", columns[3], rows[1]); btnDiv.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '/'; go = false; addToDisplay = false; } else { selectedOperator = '/'; } }); btn7 = createButton("7", columns[0], rows[2]); btn7.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("7"); } else { inputScreen.setText(inputScreen.getText() + "7"); } } else { inputScreen.setText("7"); addToDisplay = true; } go = true; }); btn8 = createButton("8", columns[1], rows[2]); btn8.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("8"); } else { inputScreen.setText(inputScreen.getText() + "8"); } } else { inputScreen.setText("8"); addToDisplay = true; } go = true; }); btn9 = createButton("9", columns[2], rows[2]); btn9.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("9"); } else { inputScreen.setText(inputScreen.getText() + "9"); } } else { inputScreen.setText("9"); addToDisplay = true; } go = true; }); btnMul = createButton("*", columns[3], rows[2]); btnMul.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '*'; go = false; addToDisplay = false; } else { selectedOperator = '*'; } }); btn4 = createButton("4", columns[0], rows[3]); btn4.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("4"); } else { inputScreen.setText(inputScreen.getText() + "4"); } } else { inputScreen.setText("4"); addToDisplay = true; } go = true; }); btn5 = createButton("5", columns[1], rows[3]); btn5.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("5"); } else { inputScreen.setText(inputScreen.getText() + "5"); } } else { inputScreen.setText("5"); addToDisplay = true; } go = true; }); btn6 = createButton("6", columns[2], rows[3]); btn6.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("6"); } else { inputScreen.setText(inputScreen.getText() + "6"); } } else { inputScreen.setText("6"); addToDisplay = true; } go = true; }); btnSub = createButton("-", columns[3], rows[3]); btnSub.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '-'; go = false; addToDisplay = false; } else { selectedOperator = '-'; } }); btn1 = createButton("1", columns[0], rows[4]); btn1.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("1"); } else { inputScreen.setText(inputScreen.getText() + "1"); } } else { inputScreen.setText("1"); addToDisplay = true; } go = true; }); btn2 = createButton("2", columns[1], rows[4]); btn2.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("2"); } else { inputScreen.setText(inputScreen.getText() + "2"); } } else { inputScreen.setText("2"); addToDisplay = true; } go = true; }); btn3 = createButton("3", columns[2], rows[4]); btn3.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("3"); } else { inputScreen.setText(inputScreen.getText() + "3"); } } else { inputScreen.setText("3"); addToDisplay = true; } go = true; }); btnAdd = createButton("+", columns[3], rows[4]); btnAdd.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '+'; go = false; addToDisplay = false; } else { selectedOperator = '+'; } }); btnPoint = createButton(".", columns[0], rows[5]); btnPoint.addActionListener(event -> { if (addToDisplay) { if (!inputScreen.getText().contains(".")) { inputScreen.setText(inputScreen.getText() + "."); } } else { inputScreen.setText("0."); addToDisplay = true; } go = true; }); btn0 = createButton("0", columns[1], rows[5]); btn0.addActionListener(event -> { if (addToDisplay) { if (Pattern.matches("[0]*", inputScreen.getText())) { inputScreen.setText("0"); } else { inputScreen.setText(inputScreen.getText() + "0"); } } else { inputScreen.setText("0"); addToDisplay = true; } go = true; }); btnEqual = createButton("=", columns[2], rows[5]); btnEqual.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '='; addToDisplay = false; } }); btnEqual.setSize(2 * BUTTON_WIDTH + 10, BUTTON_HEIGHT); btnRoot = createButton("√", columns[4], rows[1]); btnRoot.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = BigDecimal.valueOf(Math.sqrt(Double.parseDouble(inputScreen.getText()))); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '√'; addToDisplay = false; } }); btnRoot.setVisible(false); btnPower = createButton("pow", columns[4], rows[2]); btnPower.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = calculate(typedValue, new BigDecimal(inputScreen.getText()), selectedOperator); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = '^'; go = false; addToDisplay = false; } else { selectedOperator = '^'; } }); btnPower.setFont(new Font("Comic Sans MS", Font.PLAIN, 24)); btnPower.setVisible(false); btnLog = createButton("ln", columns[4], rows[3]); btnLog.addActionListener(event -> { if (!Pattern.matches(DOUBLE_OR_NUMBER_REGEX, inputScreen.getText())) return; if (go) { typedValue = BigDecimal.valueOf(Math.log(Double.parseDouble(inputScreen.getText()))); if (Pattern.matches("[-]?[\\d]+[.][0]*", typedValue.toPlainString())) { inputScreen.setText(typedValue.toPlainString()); } else { inputScreen.setText(typedValue.toPlainString()); } selectedOperator = 'l'; addToDisplay = false; } }); btnLog.setVisible(false); } private JComboBox<String> createComboBox(String[] items, int x, int y, String toolTip) { JComboBox<String> combo = new JComboBox<>(items); combo.setBounds(x, y, 140, 25); combo.setToolTipText(toolTip); combo.setCursor(new Cursor(Cursor.HAND_CURSOR)); window.add(combo); return combo; } private JButton createButton(String label, int x, int y) { JButton btn = new JButton(label); btn.setBounds(x, y, BUTTON_WIDTH, BUTTON_HEIGHT); btn.setFont(new Font("Comic Sans MS", Font.PLAIN, 28)); btn.setCursor(new Cursor(Cursor.HAND_CURSOR)); btn.setFocusable(false); window.add(btn); return btn; } private void applyTheme(Theme theme) { window.getContentPane().setBackground(hex2Color(theme.getApplicationBackground())); comboCalculatorType.setForeground(hex2Color(theme.getTextColor())); comboTheme.setForeground(hex2Color(theme.getTextColor())); inputScreen.setForeground(hex2Color(theme.getTextColor())); btn0.setForeground(hex2Color(theme.getTextColor())); btn1.setForeground(hex2Color(theme.getTextColor())); btn2.setForeground(hex2Color(theme.getTextColor())); btn3.setForeground(hex2Color(theme.getTextColor())); btn4.setForeground(hex2Color(theme.getTextColor())); btn5.setForeground(hex2Color(theme.getTextColor())); btn6.setForeground(hex2Color(theme.getTextColor())); btn7.setForeground(hex2Color(theme.getTextColor())); btn8.setForeground(hex2Color(theme.getTextColor())); btn9.setForeground(hex2Color(theme.getTextColor())); btnPoint.setForeground(hex2Color(theme.getTextColor())); btnC.setForeground(hex2Color(theme.getTextColor())); btnBack.setForeground(hex2Color(theme.getTextColor())); btnMod.setForeground(hex2Color(theme.getTextColor())); btnDiv.setForeground(hex2Color(theme.getTextColor())); btnMul.setForeground(hex2Color(theme.getTextColor())); btnSub.setForeground(hex2Color(theme.getTextColor())); btnAdd.setForeground(hex2Color(theme.getTextColor())); btnRoot.setForeground(hex2Color(theme.getTextColor())); btnLog.setForeground(hex2Color(theme.getTextColor())); btnPower.setForeground(hex2Color(theme.getTextColor())); btnEqual.setForeground(hex2Color(theme.getBtnEqualTextColor())); comboCalculatorType.setBackground(hex2Color(theme.getApplicationBackground())); comboTheme.setBackground(hex2Color(theme.getApplicationBackground())); inputScreen.setBackground(hex2Color(theme.getApplicationBackground())); btn0.setBackground(hex2Color(theme.getNumbersBackground())); btn1.setBackground(hex2Color(theme.getNumbersBackground())); btn2.setBackground(hex2Color(theme.getNumbersBackground())); btn3.setBackground(hex2Color(theme.getNumbersBackground())); btn4.setBackground(hex2Color(theme.getNumbersBackground())); btn5.setBackground(hex2Color(theme.getNumbersBackground())); btn6.setBackground(hex2Color(theme.getNumbersBackground())); btn7.setBackground(hex2Color(theme.getNumbersBackground())); btn8.setBackground(hex2Color(theme.getNumbersBackground())); btn9.setBackground(hex2Color(theme.getNumbersBackground())); btnPoint.setBackground(hex2Color(theme.getNumbersBackground())); btnC.setBackground(hex2Color(theme.getOperatorBackground())); btnBack.setBackground(hex2Color(theme.getOperatorBackground())); btnMod.setBackground(hex2Color(theme.getOperatorBackground())); btnDiv.setBackground(hex2Color(theme.getOperatorBackground())); btnMul.setBackground(hex2Color(theme.getOperatorBackground())); btnSub.setBackground(hex2Color(theme.getOperatorBackground())); btnAdd.setBackground(hex2Color(theme.getOperatorBackground())); btnRoot.setBackground(hex2Color(theme.getOperatorBackground())); btnLog.setBackground(hex2Color(theme.getOperatorBackground())); btnPower.setBackground(hex2Color(theme.getOperatorBackground())); btnEqual.setBackground(hex2Color(theme.getBtnEqualBackground())); } }
And CalculatorUITest.java:
package com.houarizegai.calculator; import com.houarizegai.calculator.ui.CalculatorUI; import org.junit.jupiter.api.BeforeEach; import org.junit.jupiter.params.ParameterizedTest; import org.junit.jupiter.params.provider.CsvSource; import java.math.BigDecimal; import static org.junit.jupiter.api.Assertions.assertEquals; class CalculatorUITest { private CalculatorUI calculatorUI; @BeforeEach void setUp() { calculatorUI = new CalculatorUI(); } @ParameterizedTest @CsvSource({"3,5,+,8", "2,8,-,-6", "44.5,10,*,445", "320,5,/,64", "3,5,%,3", "5,3,^,125"}) void testCalculation(BigDecimal firstNumber, BigDecimal secondNumber, char operator, BigDecimal expectedResult) { assertEquals(expectedResult, calculatorUI.calculate(firstNumber, secondNumber, operator)); } }
Major changes:
public BigDecimal calculate(BigDecimal firstNumber, BigDecimal secondNumber, char operator) { switch (operator) { case '+': return firstNumber.add(secondNumber).stripTrailingZeros(); case '-': return firstNumber.subtract(secondNumber).stripTrailingZeros(); case '*': return firstNumber.multiply(secondNumber).stripTrailingZeros(); case '/': return firstNumber.divide(secondNumber, 16, RoundingMode.HALF_UP).stripTrailingZeros(); case '%': return firstNumber.remainder(secondNumber).stripTrailingZeros(); case '^': double result=Math.pow(firstNumber.doubleValue(),secondNumber.doubleValue()); return new BigDecimal(result).setScale(16, RoundingMode.HALF_UP).stripTrailingZeros(); default: return secondNumber.stripTrailingZeros(); } }
The value typedValue changed from double to BigDecimal, and all related codes were modified accordingly.
The text was updated successfully, but these errors were encountered:
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Using Bigdecimal for calculations ensures that precision is not lost.
It can solve problems such as 0.1+0.2=0.300000000000000004
// src/main/com/houarizegai/calculator/ui/CalculatorUI.java
And CalculatorUITest.java:
Major changes:
The value typedValue changed from double to BigDecimal, and all related codes were modified accordingly.
The text was updated successfully, but these errors were encountered: