First of all, Welcome to Roadfood!
Oakland, the section of the city where the University of Pittsburgh is located has lots of great food options within walking distance of the campus.
Like Mosca said, Original Hot Dog Shop is a local institution and reviewed here on Roadfood. Make sure you get an order of their excellent fries.
Another local institution, Primanti Brothers, famous for putting coleslaw and fries right on the sandwich, has a branch in Oakland on Forbes Avenue. My advice would be to go for either the capicola or kielbasa sandwiches. Here is their Roadfood review.
The best ice cream place in the city, Dave & Andy’s is located on Atwood Street. Rick Sebak, a Pittsburgh native who makes those wonderful food shows for PBS, including An Ice Cream Show, named this one of the top 10 ice cream shops in the country.
For breakfast, you must go to Pamela’s. This is a small Pittsburgh chain with five locations around the city and they do have one right on Forbes Avenue. Everything is good, but I especially like the ultra-thin strawberry hotcakes.
If you want to try something a little different, you may want to consider The Spice Island Tea House, which has Pan-Asian food and is one of the city’s hidden little gems.
After that, if there is a specific type of food (Mexican, Indian, Italian, etc.) you want a recommendation for, let me know and I will be happy to help.
Edited to correct the name of the street…..