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CS50x - Harvard University's Introduction to Computer Science and Programming


CS50x is an introductory course offered by Harvard University that delves into the world of computer science and the art of programming. This course is designed to cater to both majors and non-majors, regardless of their prior programming experience. Led by the renowned instructor David J. Malan, CS50x equips students with the skills to think algorithmically and solve problems efficiently. The course covers a wide range of topics, including abstraction, algorithms, data structures, encapsulation, resource management, security, software engineering, and web development. Programming languages such as C, Python, SQL, JavaScript, CSS, and HTML are taught, with problem sets inspired by real-world domains like biology, cryptography, finance, forensics, and gaming. CS50, the on-campus version of CS50x, is Harvard's largest course.

Course Structure

CS50x offers a self-paced learning experience, allowing students to progress through the course at their own convenience. To earn a certificate, students must achieve a satisfactory score on 9 problem sets (programming assignments) and successfully complete a final project.

Honor Code

HarvardX, the platform hosting CS50x, enforces a strict honor code that all enrollees must adhere to. Violations of this code can lead to corrective actions, including dismissal from the course and revocation of any certificates obtained. No refunds will be issued in cases of honor code violations. Students who are taking CS50x as part of another program are also subject to the academic policies of those programs.

Research Participation

By registering for CS50x, students become part of a larger research effort to study the science of learning. Their participation in the course contributes valuable data to ongoing research about online education and learning methods.

Inclusive Environment

Harvard University and HarvardX are committed to maintaining a safe and inclusive educational and work environment. Discrimination and harassment are strictly prohibited, and all members of the CS50x community are expected to adhere to Harvard's policies on nondiscrimination, including sexual harassment, as well as the edX Terms of Service. Any concerns or questions related to these policies can be directed to or reported through the edX contact form.

Certificate Eligibility

Upon successfully submitting and receiving a score of at least 70% on each of the course's problem sets and labs, as well as the final project, students are eligible to receive a free CS50 Certificate. For those seeking a verified certificate from edX, registration is available at Further information can be found in the FAQs, and any unanswered questions can be directed to

Taught by

David J. Malan

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