CodeRunner

Bad answer (syntax error)

Bad answer (wrong output)

Bad answer (runtime error)

Right answer

C Function (hidden test case shown to teacher)

pylint-checked question: bad answer

Java Class: teacher view (showing hidden test case)

Use of the Precheck capability

Easy template-grader example: right answer

Easy template-grade example: partially-right answer

Custom grader: right answer

Custom grader: wrong answer

Custom grader: syntax error

Before clicking "Show differences"

After clicking "Show differences"

Question authoring: the trivial Python3 sqr function

The Graph UI in action