C program using priority queue(data structures)

Write a program to simulate the following situation. Computer is a multitasking device. We need to download some document as well as listen music and play game simultaneously. There is a system queue which decide which task to be done first. Assume that for download application the priority is highest and game playing is the lowest priority. After completion of one type of tasks like all download operations then the second queue will be processed.
C program
This is problem statement, you should know data structures using c programming and it's urgent 24 hours.