add a simple calculator with GUI and history

Author: SilverShadow1111

projects/simple_calculator_with_history/README.md

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+# Simple Calculator with History
+
+A modern calculator application built with Python and Tkinter that includes a calculation history feature.
+
+## Features
+
+- Basic arithmetic operations (+, -, *, /)
+- Parentheses support for complex expressions
+- Calculation history display
+- Clear history functionality
+- Modern GUI with clean design
+- Backspace button to correct mistakes
+- Error handling for invalid expressions
+
+## Requirements
+
+- Python 3.x
+- Tkinter (usually comes with Python installation)
+
+## How to Run
+
+1. Make sure you have Python installed on your system
+2. Navigate to the project directory
+3. Run the following command:
+   ```
+   python calculator.py
+   ```
+
+## Usage
+
+- Use the number buttons (0-9) and operators (+, -, *, /) to create expressions
+- Press '=' to calculate the result
+- Press 'C' to clear the current expression
+- Press '←' to delete the last character
+- Use parentheses '(' and ')' for complex expressions
+- View calculation history on the right side
+- Click "Clear History" to remove all history entries
+
+## Error Handling
+
+The calculator will display "Error" if:
+- The expression is invalid
+- Division by zero is attempted
+- Parentheses are not properly matched
+

projects/simple_calculator_with_history/calculator.py

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+import tkinter as tk
+from tkinter import ttk
+import math
+
+class Calculator:
+    def __init__(self, root):
+        self.root = root
+        self.root.title("Calculator with History")
+        self.root.geometry("600x400")
+        self.root.configure(bg="#f0f0f0")
+        
+        self.current_expression = ""
+        self.history = []
+        
+        self.create_frames()
+        
+        self.create_display()
+        
+        self.create_buttons()
+        
+        self.create_history_display()
+
+    def create_frames(self):
+
+        self.main_container = ttk.Frame(self.root)
+        self.main_container.pack(expand=True, fill="both", padx=10, pady=10)
+        
+        self.calculator_frame = ttk.Frame(self.main_container)
+        self.calculator_frame.pack(side="left", expand=True, fill="both", padx=(0, 5))
+        
+        self.history_frame = ttk.Frame(self.main_container)
+        self.history_frame.pack(side="right", expand=True, fill="both", padx=(5, 0))
+
+    def create_display(self):
+
+        self.display = ttk.Entry(self.calculator_frame, justify="right", font=("Arial", 20))
+        self.display.pack(fill="x", padx=5, pady=5)
+
+    def create_buttons(self):
+
+        button_frame = ttk.Frame(self.calculator_frame)
+        button_frame.pack(expand=True, fill="both")
+        
+        buttons = [
+            ('7', 1, 0), ('8', 1, 1), ('9', 1, 2), ('/', 1, 3),
+            ('4', 2, 0), ('5', 2, 1), ('6', 2, 2), ('*', 2, 3),
+            ('1', 3, 0), ('2', 3, 1), ('3', 3, 2), ('-', 3, 3),
+            ('0', 4, 0), ('.', 4, 1), ('=', 4, 2), ('+', 4, 3),
+            ('C', 5, 0), ('←', 5, 1), ('(', 5, 2), (')', 5, 3),
+        ]
+        
+        for (text, row, col) in buttons:
+            button = ttk.Button(button_frame, text=text, command=lambda t=text: self.button_click(t))
+            button.grid(row=row, column=col, sticky="nsew", padx=2, pady=2)
+        
+        for i in range(6):
+            button_frame.grid_rowconfigure(i, weight=1)
+        for i in range(4):
+            button_frame.grid_columnconfigure(i, weight=1)
+
+    def create_history_display(self):
+
+        history_label = ttk.Label(self.history_frame, text="History", font=("Arial", 14))
+        history_label.pack(pady=5)
+        
+        self.history_listbox = tk.Listbox(self.history_frame, font=("Arial", 12))
+        self.history_listbox.pack(expand=True, fill="both")
+        
+        clear_history_btn = ttk.Button(self.history_frame, text="Clear History", command=self.clear_history)
+        clear_history_btn.pack(pady=5)
+
+    def button_click(self, value):
+        if value == "=":
+            try:
+                result = eval(self.current_expression)
+
+                history_entry = f"{self.current_expression} = {result}"
+                self.history.append(history_entry)
+                self.history_listbox.insert(0, history_entry)
+
+                self.current_expression = str(result)
+                self.display.delete(0, tk.END)
+                self.display.insert(tk.END, self.current_expression)
+            except:
+                self.display.delete(0, tk.END)
+                self.display.insert(tk.END, "Error")
+                self.current_expression = ""
+        elif value == "C":
+            self.current_expression = ""
+            self.display.delete(0, tk.END)
+        elif value == "←":
+            self.current_expression = self.current_expression[:-1]
+            self.display.delete(0, tk.END)
+            self.display.insert(tk.END, self.current_expression)
+        else:
+            self.current_expression += value
+            self.display.delete(0, tk.END)
+            self.display.insert(tk.END, self.current_expression)
+
+    def clear_history(self):
+        self.history = []
+        self.history_listbox.delete(0, tk.END)
+
+if __name__ == "__main__":
+    root = tk.Tk()
+    app = Calculator(root)
+    style = ttk.Style()
+    style.theme_use('clam')
+    root.mainloop()