radioButton.py

from tkinter import *

class Tela:
    def __init__(self):
        self.janela = Tk()

        self.valor = StringVar()

        self.rb1 = Radiobutton(self.janela, text='Python', variable=self.valor, value='Python', command=self.mostrar)
        self.rb1.pack()
        self.rb1.select()

        self.rb2 = Radiobutton(self.janela, text='Java', variable=self.valor, value='Java', command=self.mostrar)
        self.rb2.pack()

        self.rb3 = Radiobutton(self.janela, text='C++', variable=self.valor, value='C++', command=self.mostrar)
        self.rb3.pack()

        self.saida = Label(self.janela)
        self.saida.pack()

        mainloop()

    def mostrar(self):
        escolha = self.valor.get()
        if escolha == 'Python':
            self.saida['text'] = "print('Olá, mundo')"
        elif escolha == 'Java':
            self.saida['text'] = "System.out.println('Olá, mundo')"
        else:
            self.saida['text'] = "std::cout << 'Olá, mundo' << std::end|"

minhaTela = Tela()