Removing an item from an itemStack from the NBT

[clowcadia]

Hey I am back!!!

Like the topic name says, I am trying to make the itemStack in the NBT decremented by one. I did some research, a lot of the stuff is outdated and far more complex then i think it should be. I am sure the solution is a simple one liner. Any help will be greatly appreciated.

[Animefan8888]

Does it have to be with the NBTTagCompound? Why cant you just use an ItemStack variable? And if you need to figure it out and use NBT then just look at the ItemStack constructor that takes in an NBTTagCompound and only an NBTTagCompound or the writeToNBT method.