如何写出一个简易计算器

wen 实用脚本 2026-08-03 233

本文目录导读：

如何写出一个简易计算器

纯Python命令行版本（最简单）
图形界面版本（Tkinter）
Web版本（Flask + HTML）
使用说明
关键知识点

我来帮你写一个简易计算器,这里提供几个不同版本的实现：

纯Python命令行版本（最简单）

def simple_calculator():
    """命令行简易计算器"""
    print("简易计算器")
    print("支持操作: +, -, *, /")
    while True:
        try:
            # 获取用户输入
            num1 = float(input("请输入第一个数字: "))
            operator = input("请输入运算符 (+,-,*,/,q退出): ")
            if operator == 'q':
                print("再见！")
                break
            num2 = float(input("请输入第二个数字: "))
            # 执行计算
            if operator == '+':
                result = num1 + num2
            elif operator == '-':
                result = num1 - num2
            elif operator == '*':
                result = num1 * num2
            elif operator == '/':
                if num2 == 0:
                    print("错误：不能除以0！")
                    continue
                result = num1 / num2
            else:
                print("无效运算符！")
                continue
            print(f"结果: {result}")
            print("-" * 30)
        except ValueError:
            print("错误：请输入有效数字！")
        except Exception as e:
            print(f"发生错误: {e}")
if __name__ == "__main__":
    simple_calculator()

图形界面版本（Tkinter）

import tkinter as tk
class Calculator:
    def __init__(self, root):
        self.root = root
        self.root.title("简易计算器")
        self.root.geometry("300x400")
        # 显示结果
        self.result_var = tk.StringVar()
        self.result_var.set("0")
        # 创建显示框
        self.display = tk.Entry(
            root, 
            textvariable=self.result_var,
            font=("Arial", 20),
            justify="right",
            state="readonly"
        )
        self.display.pack(fill="x", padx=10, pady=10, ipady=10)
        # 创建按钮
        self.create_buttons()
    def create_buttons(self):
        # 按钮布局
        buttons = [
            '7', '8', '9', '/',
            '4', '5', '6', '*',
            '1', '2', '3', '-',
            '0', '.', '=', '+'
        ]
        # 创建按钮框架
        button_frame = tk.Frame(self.root)
        button_frame.pack(fill="both", expand=True, padx=10, pady=10)
        # 创建按钮
        row = 0
        col = 0
        for button_text in buttons:
            cmd = lambda x=button_text: self.click(x)
            btn = tk.Button(
                button_frame,
                text=button_text,
                font=("Arial", 16),
                command=cmd,
                relief="groove",
                bd=2
            )
            btn.grid(row=row, column=col, sticky="nsew", padx=2, pady=2)
            col += 1
            if col > 3:
                col = 0
                row += 1
        # 清除按钮（单独放置）
        clear_btn = tk.Button(
            button_frame,
            text="C",
            font=("Arial", 16),
            command=self.clear,
            relief="groove",
            bd=2,
            bg="#ff9999"
        )
        clear_btn.grid(row=row, column=0, sticky="nsew", padx=2, pady=2)
        # 删除按钮
        delete_btn = tk.Button(
            button_frame,
            text="⌫",
            font=("Arial", 16),
            command=self.delete,
            relief="groove",
            bd=2,
            bg="#99ff99"
        )
        delete_btn.grid(row=row, column=1, columnspan=3, sticky="nsew", padx=2, pady=2)
        # 配置网格权重
        for i in range(4):
            button_frame.grid_columnconfigure(i, weight=1)
        for i in range(5):
            button_frame.grid_rowconfigure(i, weight=1)
    def click(self, value):
        current = self.result_var.get()
        if value == '=':
            try:
                # 安全执行计算
                result = eval(current)
                self.result_var.set(str(result))
            except:
                self.result_var.set("错误")
        elif value in ['+', '-', '*', '/']:
            # 运算符处理
            if current and current[-1] not in '+-*/':
                self.result_var.set(current + value)
            elif current[-1:] in '+-*/':
                # 替换运算符
                self.result_var.set(current[:-1] + value)
        elif value == '.':
            # 小数点处理
            if current.count('.') == 0 or current[-1] in '+-*/':
                self.result_var.set(current + value)
        else:
            # 数字处理
            if current == "0":
                self.result_var.set(value)
            else:
                self.result_var.set(current + value)
    def clear(self):
        self.result_var.set("0")
    def delete(self):
        current = self.result_var.get()
        if len(current) > 1:
            self.result_var.set(current[:-1])
        else:
            self.result_var.set("0")
if __name__ == "__main__":
    root = tk.Tk()
    calculator = Calculator(root)
    root.mainloop()

Web版本（Flask + HTML）

# 需安装: pip install flask
from flask import Flask, request, render_template_string
app = Flask(__name__)
HTML_TEMPLATE = """
<!DOCTYPE html>
<html>
<head>简易计算器</title>
    <style>
        body { font-family: Arial; display: flex; justify-content: center; padding: 50px; }
        .calculator { background: #f4f4f4; padding: 20px; border-radius: 10px; box-shadow: 0 2px 5px rgba(0,0,0,0.2); }
        input[type="text"] { width: 200px; padding: 10px; font-size: 20px; margin-bottom: 10px; }
        table { margin: 0 auto; }
        button { width: 50px; height: 50px; font-size: 18px; margin: 2px; cursor: pointer; border: none; background: white; border-radius: 5px; }
        button:hover { background: #ddd; }
    </style>
</head>
<body>
    <div class="calculator">
        <h2>简易计算器</h2>
        <form method="POST">
            <input type="text" name="expression" value="{{ expression }}" readonly>
            <table>
                {% for row in buttons %}
                <tr>
                    {% for btn in row %}
                    <td><button type="submit" name="expression" value="{{ expression }}{{ btn }}">{{ btn }}</button></td>
                    {% endfor %}
                </tr>
                {% endfor %}
                <tr>
                    <td colspan="2"><button type="submit" name="expression" value="">C</button></td>
                    <td colspan="2"><button type="submit" name="expression" value="=" style="background: #4CAF50; color: white;">=</button></td>
                </tr>
            </table>
        </form>
        {% if result %}
        <p>结果: {{ result }}</p>
        {% endif %}
    </div>
</body>
</html>
"""
@app.route('/', methods=['GET', 'POST'])
def calculator():
    expression = ""
    result = None
    if request.method == 'POST':
        expression = request.form.get('expression', '')
        if expression.endswith('='):
            expression = expression[:-1]
            try:
                result = eval(expression)
                expression = str(result)
            except:
                result = "错误"
    # 按钮布局
    buttons = [
        ['7', '8', '9', '/'],
        ['4', '5', '6', '*'],
        ['1', '2', '3', '-'],
        ['0', '.', '/', '+']
    ]
    return render_template_string(
        HTML_TEMPLATE, 
        buttons=buttons, 
        expression=expression,
        result=result
    )
if __name__ == '__main__':
    app.run(debug=True)