What are the differences and similarities between Stanley and Zero in Louis Sachar's Holes?

Stanley "Caveman" Yelnats and Zero are first and foremost bound by the crime for which Stanley is doing time at Camp Green Lake. Stanley is wrongfully accused of stealing a pair of sneakers—shoes which, in reality, Zero had stolen out of desperation. The intersection of their personal and family histories both happened to land them at the same juvenile detention center. Once there, it is clear that both Stanley and Zero possess personal grit and...

Stanley "Caveman" Yelnats and Zero are first and foremost bound by the crime for which Stanley is doing time at Camp Green Lake. Stanley is wrongfully accused of stealing a pair of sneakers—shoes which, in reality, Zero had stolen out of desperation. The intersection of their personal and family histories both happened to land them at the same juvenile detention center. Once there, it is clear that both Stanley and Zero possess personal grit and resilience, a distaste for injustice, and a desire to see the wrongs of the world righted. Together, they learn to embrace their courage and fight the system which is oppressing them.

Their differences lie in their environments of origin and their upbringing. Zero is extremely uneducated and comes from a place of poverty (having been left homeless after his mother abandoned him), whereas Stanley has attended school, possesses a family, and is comfortable enough, although not by any means rich. Zero is the best digger at the camp despite his small stature, whereas Stanley possesses more intellectual acumen.