Sample program to show how the default error type is implemented.

Sample program to show how to use error variables to help the caller determine the exact error being returned.

http://golang.org/src/pkg/encoding/json/decode.go Sample program to show how to implement a custom error type based on the json package in the standard library.

Package example4 provides code to show how to implement behavior as context.

Sample program to show see if the class can find the bug.

Sample program to show how wrapping errors work with pkg/errors.

Sample program to show how wrapping errors work with the stdlib.