文本框输入a，b，c的值，输出一元二次方程的解。

以下是Python实现一元二次方程求解的代码，其中使用了tkinter库实现了一个简单的窗口界面，用户可以在文本框中输入方程的各项系数，点击按钮后在文本区中显示方程的两个根（如果有的话）：

import tkinter as tk
import math

class QuadraticEquation:
    def __init__(self, a, b, c):
        self.a = a
        self.b = b
        self.c = c

    def getDiscriminant(self):
        return self.b * self.b - 4 * self.a * self.c

    def getRoot1(self):
        if self.getDiscriminant() < 0:
            return None
        else:
            return (-self.b + math.sqrt(self.getDiscriminant())) / (2 * self.a)

    def getRoot2(self):
        if self.getDiscriminant() < 0:
            return None
        else:
            return (-self.b - math.sqrt(self.getDiscriminant())) / (2 * self.a)

class Application(tk.Frame):
    def __init__(self, master=None):
        super().__init__(master)
        self.master = master
        self.pack()
        self.create_widgets()

    def create_widgets(self):
        self.a_label = tk.Label(self)
        self.a_label["text"] = "a:"
        self.a_label.pack(side="left")

        self.a_entry = tk.Entry(self)
        self.a_entry.pack(side="left")

        self.b_label = tk.Label(self)
        self.b_label["text"] = "b:"
        self.b_label.pack(side="left")

        self.b_entry = tk.Entry(self)
        self.b_entry.pack(side="left")

        self.c_label = tk.Label(self)
        self.c_label["text"] = "c:"
        self.c_label.pack(side="left")

        self.c_entry = tk.Entry(self)
        self.c_entry.pack(side="left")

        self.calculate_button = tk.Button(self)
        self.calculate_button["text"] = "Calculate"
        self.calculate_button["command"] = self.calculate
        self.calculate_button.pack(side="left")

        self.quit_button = tk.Button(self, text="Quit", command=self.master.destroy)
        self.quit_button.pack(side="left")

        self.result_text = tk.Text(self)
        self.result_text.pack()

    def calculate(self):
        a = float(self.a_entry.get())
        b = float(self.b_entry.get())
        c = float(self.c_entry.get())

        equation = QuadraticEquation(a, b, c)

        root1 = equation.getRoot1()
        root2 = equation.getRoot2()

        if root1 is None and root2 is None:
            self.result_text.delete("1.0", tk.END)
            self.result_text.insert(tk.END, "No real roots")
        elif root1 is None:
            self.result_text.delete("1.0", tk.END)
            self.result_text.insert(tk.END, "The equation has one root: " + str(root2))
        elif root2 is None:
            self.result_text.delete("1.0", tk.END)
            self.result_text.insert(tk.END, "The equation has one root: " + str(root1))
        else:
            self.result_text.delete("1.0", tk.END)
            self.result_text.insert(tk.END, "The roots are " + str(root1) + " and " + str(root2))

root = tk.Tk()
app = Application(master=root)
app.mainloop()