The traditional assessment approach, in which one single written examination counts toward a student's total score, no longer meets new demands of programming language education. Based on a peer code review process model, we developed an online assessment system called "EduPCR" and used a novel approach to assess the learning of computer programming languages. Using this approach, students peer review programs written by other students, share ideas and make suggestions to achieve an objective of collaborative and interactive learning. Teachers assess and give scores to students based on their performance in writing, reviewing and revising programs and their abidance to a peer code review process. After using this approach in two courses in two consecutive semesters, we observed significant improvements of student learning in various aspects. We also conducted two questionnaire surveys and two interviews. The survey data and the interview report indicated that this assessment approach demonstrates high practical values in assessing student learning outcomes in programming languages. Additionally, this approach leads to several interesting research topics for future research in this field. (Contains 5 tables and 14 figures.)