Delhi University or NIT Patna - which one is the better choice?

NIT Patna is definitely preferable over DU. Both Civil Engineering and Computer Sciences subjects are good. But you have an interest in Computer Science. So try for a seat in computer science in NIT. If there is no chance, then opt for DU. If you don't have a chance in DU also then opt for Civil ENgineering.

The computer science deepartment of Delhi University is renowned and the campus placement facility is excellent. Major companies recruit students from the campus itself. The faculty is also very good. On the other hand, NIT, Patna is recently established in 2004. Although it is a good engineering college in Bihar, but if we compare the computer science department of Delhi with civil engineering department of NIT-Patna, I think you should opt for the first one, provided you have interest in studying computer science.

The course should be persued with your own interest and as you have indicated your passion towards so going ahead with the same stream from DU would not be a bad option. Don't take admission for such a course which will cause a major strain at the later stage.
NIT Patna though an established institution but offering of the Civil - engineering course may spoil your interest in the subsequent time.
Take admission with a single minded devotion and an effort should be made to excel well in your Computer - science stream so as to make a lucrative career in this field.

You should go with DU instead NIT, Patna. Delhi University get highest ranked in India. Why DU is because of the low fees. Number one college or university for arts, science and engineering. DU holds 81st rank in Asia. It guaranteed provide the placement to the final year students. So my advice is to avail yourself in college of Delhi university.