Most common fixes students use to improve the correctness of their programs

Teach students how to program is the main goal of most introductory CS courses. In fact, programming is one of the basic skills a professional in CS should have. However, there are many difficulties students face when they are learning how to program and, consequently, it is common introductory programming courses have high dropout rates. The purpose of this paper is to identify and discuss the most common fixes students use to improve the correctness of their programs. The findings can be useful to help students to produce more correct programs and highlight issues about possible difficulties they are having. To do so, we used the BLACKBOX data collection, which stores the actions of the BLUEJ programming environment users. The main idea was to observe the modifications students did in their source codes that made a failed JUNIT test case become succeeded. The results suggest the majority of fixes students use in their source codes are related either to the change of expressions or to the restructuring of code, reflecting difficulties in logic and problem solving among students.