Prison: Punishment or Rehabilitation?

Why are prisoners in prison anyway? Are convicts detained and imprisoned for their good or our safety? Is the current system of prison working well? Is the prison pleasant for the inmate, should it be pleasant for the inmate. Are inmates being educated in the ways of society or the ways of crime? Is prison "a walk in the park" or "a walk in the dark"? Some important questions need to be asked and answered …

…for 10 years then they should not be allowed to go free after 4 years. Let the judge assign the time and the prisoner serve it. The prisoner should also pay for his own cost of living. An "Inside Out" program of some sort would provide a service to community such as road work or other, and would earn the convict money to pay for his living and raise money for after the completion of his term.