shaming calculator

lesson2/src/Calculator.java

@@ -0,0 +1,12 @@
+import javax.swing.*;
+
+public class Calculator extends JFrame {
+
+    Calculator(){
+        setTitle("Calculator");
+        add(new MyJPanel());
+        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
+        setSize(500,500);
+        setVisible(true);
+    }
+}

lesson2/src/ExpressionManager.java

@@ -0,0 +1,54 @@
+public class ExpressionManager {
+    MyJPanel myJPanel;
+    String[] operands;
+
+    ExpressionManager(MyJPanel myJPanel){
+        this.myJPanel = myJPanel;
+        operands = new String[]{"+","-","*","/"};
+    }
+
+
+
+    public String[] splitOperands(){
+        String expression = myJPanel.getExpressionString();
+        String operands[] = expression.split(findOperator(expression));
+        return operands;
+    }
+
+    String findOperator(String expression){
+        String operand = null;
+        for (int i = 0; i < operands.length; i++) {
+            if (expression.indexOf(operands[i])>0){
+                operand =  operands[i];
+                if (operand.equals("+")){
+                    operand = "\\+";
+                }else if (operand.equals("*")){
+                    operand="\\*";
+                }
+            }
+        }
+        return operand;
+    }
+
+    double getResult(){
+        double firstOperand = Double.parseDouble(splitOperands()[0]);
+        double secondOperand = Double.parseDouble(splitOperands()[1]);
+        double result = 0;
+        String operator = findOperator(myJPanel.getExpressionString());
+        switch (operator){
+            case "-":
+                result = firstOperand - secondOperand;
+                break;
+            case "/":
+                result = firstOperand / secondOperand;
+                break;
+            case "\\+":
+                result = firstOperand + secondOperand;
+                break;
+            case"\\*":
+                result = firstOperand * secondOperand;
+                break;
+        }
+            return result;
+    }
+}

lesson2/src/Main.java

@@ -0,0 +1,5 @@
+public class Main {
+    public static void main(String[] args) {
+        new Calculator();
+    }
+}

lesson2/src/MyJPanel.java

@@ -0,0 +1,147 @@
+import javax.swing.*;
+import java.awt.*;
+
+public class MyJPanel extends JPanel {
+
+    private double firstOperand = 0.0;
+    private double secondOperand = 0.0;
+    private double result = 0.0;
+    JTextField operationPanel;
+
+
+    MyJPanel(){
+        setLayout(null);
+        setBackground(Color.BLACK);
+
+        operationPanel = new JTextField();
+        operationPanel.setEditable(false);
+
+        JButton b7 = new JButton("7");
+        JButton b8 = new JButton("8");
+        JButton b9 = new JButton("9");
+        JButton b4 = new JButton("4");
+        JButton b5 = new JButton("5");
+        JButton b6 = new JButton("6");
+        JButton b1 = new JButton("1");
+        JButton b2 = new JButton("2");
+        JButton b3 = new JButton("3");
+        JButton b0 = new JButton("0");
+
+        JButton plus = new JButton("+");
+        JButton minus = new JButton("-");
+        JButton divide = new JButton("/");
+        JButton multiple = new JButton("*");
+        JButton clear = new JButton("clear");
+        JButton equal = new JButton("=");
+
+        operationPanel.setBounds(50,20,380,50);
+        b7.setBounds(50,100,70,70);
+        b8.setBounds(150,100,70,70);
+        b9.setBounds(250,100,70,70);
+        b4.setBounds(50,180,70,70);
+        b5.setBounds(150,180,70,70);
+        b6.setBounds(250,180,70,70);
+        b1.setBounds(50,260,70,70);
+        b2.setBounds(150,260,70,70);
+        b3.setBounds(250,260,70,70);
+        b0.setBounds(50,340,70,70);
+
+        divide.setBounds(350,100,70,70);
+        multiple.setBounds(350,180,70,70);
+        minus.setBounds(350,260,70,70);
+        plus.setBounds(350,340,70,70);
+
+        clear.setBounds(150,340,70,70);
+        equal.setBounds(250,340,70,70);
+
+        add(operationPanel);
+        add(b7);
+        add(b8);
+        add(b9);
+        add(b4);
+        add(b5);
+        add(b6);
+        add(b1);
+        add(b2);
+        add(b3);
+        add(b0);
+
+        add(divide);
+        add(multiple);
+        add(minus);
+        add(plus);
+        add(clear);
+        add(equal);
+
+        b1.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 1);
+        });
+
+        b2.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 2);
+        });
+
+        b3.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 3);
+        });
+
+        b4.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 4);
+        });
+        b5.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 5);
+        });
+        b6.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 6);
+        });
+        b7.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 7);
+        });
+        b8.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 8);
+        });
+        b9.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 9);
+        });
+        b0.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + 0);
+        });
+
+        divide.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() +"/");
+
+
+        });
+
+        multiple.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + "*");
+
+
+        });
+
+        minus.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + "-");
+
+        });
+
+        plus.addActionListener(e -> {
+            operationPanel.setText(operationPanel.getText() + "+");
+
+        });
+
+        clear.addActionListener(e -> {
+            operationPanel.setText("");
+        });
+
+        equal.addActionListener(e -> {
+            ExpressionManager expressionManager = new ExpressionManager(this);
+            operationPanel.setText(String.valueOf(expressionManager.getResult()));
+        });
+    }
+
+
+    String getExpressionString(){
+        return operationPanel.getText();
+    }
+
+}