Mayella has committed crimes against tom and against the state (false accusation, lying under oath, even "murder" of an innocent man) because she is ashamed of breaking a "code" and "tempting a negro." what’s the difference between a law and a code

A Law is a set of rules accepted by the country, whereas code is a standard accepted by an individual, society, or a class.

Explanation:

In "To Kill A Mockingbird," in chapter 20, Mayella breaks both "law" and "code."

She breaks law by giving false statement against Tom in the court. And she broke the code, by tempting a Negro.

She accused Tom, who is black, of ra-pe and on the other hand, she lu-sts after a black man. However, breaking of law is more powerful because it involves punishment whereas breaking of code does not.