Answer:
Before going into similarities and differences between sharecroppers and slaves, we need to know that while sharecroppers were free, but really poor, farmers who worked the land of a tenant, slaves were basically people without any rights, without any property, and who were, themselves, the property of someone else.
Having established that, which in essence shows the difference between the two, we will continue with differences. Essentially, sharecroppers were free people, both black and white, when it came to the U.S., while slaves were not. Second, sharecroppers were given a land to tend to for a tenant, but they received reward, and payment, for their work, while slaves did not. In fact, they were not necessarily used for working just the land. The sharecropper remained in his land, and shared the earnings with the tenant, but overall, he could lead his own life as he wished. Slaves were completely dependent on their masters and their lives were not their own; everything depended on the master and his family.
As for similarities, well, we can say that in some ways, both slaves and sharecroppers were dependent on someone else´s higher power and control. Both of them, usually at least for the slaves, worked the lands and plantations for their owners. Both had to share with the owner, what they had. Both had their work depending on the land that someone else owned. Both were poor, and most, both sharecroppers and slaves, were uneducated.