#COMANDA
def b():
    dulj=float(textbox1.get())
    šir=float(textbox2.get())
    vis=float(textbox3.get())
    vol=round(dulj*šir*vis,2)
    rez = Label(a,text = "Volumen kvadrata je: " +str(vol))
    rez.place(x = 350, y=350)


    

    
#/////////////////////////////////////////////////
              

#labels

#1.
ispis = Label(a, text = "duljina" , bg = "black"
              , fg="white", font=("Arial",12))
ispis.place(x =50, y=50)

#2.
ispis = Label(a, text = "širina" , bg = "black"
              , fg="white", font=("Arial",12))
ispis.place(x =50, y=100)
#3.
ispis = Label(a, text = "visina" , bg = "black"
              , fg="white", font=("Arial",12))
ispis.place(x =50, y=150)
#4.
ispis = Label(a, text = "Hello world" , bg = "black"
              , fg="white", font=("Arial",12))
ispis.place(x =50, y=200)

#entrys:

#1
textbox1 = Entry(a,width=12)
textbox1.place(x =200, y=50)

#2
textbox2 = Entry(a,width=12)
textbox2.place(x =200, y=100)

#3
textbox3 = Entry(a,width=12)
textbox3.place(x =200, y=150)

#GUMB

#1
gumb2=Button(a,text="izracunja volumen", command=b)
gumb2.place(x=180,y=300,width=120)