You can check the problem sets here
Runs a plurality election
Every voter gets to vote for one candidate. At the end of the election, whichever candidate has the greatest number of votes is declared the winner.
$ ./plurality Alice Bob Charlie
Number of voters: 4
Vote: Alice
Vote: Bob
Vote: Charlie
Vote: Alice
Alice
Runs a runoff election
It's a ranked-choice voting system, in which voters can vote for more than one candidate
$ ./runoff Alice Bob Charlie
Number of voters: 3
Rank 1: Alice
Rank 2: Bob
Rank 3: Charlie
Rank 1: Alice
Rank 2: Charlie
Rank 3: Bob
Rank 1: Bob
Rank 2: Alice
Rank 3: Charlie
Alice