Scala constructing a "List", read from stdin, output to stdout - scala

Question

I'm trying to read formatted inputs from stdin using Scala:
The equivalent C++ code is here:
int main() {
int t, n, m, p;
cin >> t;
for (int i = 0; i < t; ++i) {
cin >> n >> m >> p;
vector<Player> players;
for (int j = 0; j < n; ++j) {
Player player;
cin >> player.name >> player.pct >> player.height;
players.push_back(player);
}
vector<Player> ret = Solve(players, n, m, p);
cout << "Case #" << i + 1 << ": ";
for (auto &item : ret) cout << item.name << " ";
cout << endl;
}
return 0;
}
Where in the Scala code, I'd like to Use
players: List[Player], n: Int, m: Int, p: Int
to store these data.
Could someone provide a sample code?
Or, just let me know how to:
how the "main()" function work in scala
read formatted text from stdin
efficiently constructing a list from inputs (as list are immutable, perhaps there's a more efficient way to construct it? rather than having a new list as each element comes in?)
output formatted text to stdout
Thanks!!!

Answer 1

I don't know C++, but something like this should work :
def main(args: Array[String]) = {
val lines = io.Source.stdin.getLines
val t = lines.next.toInt
// 1 to t because of ++i
// 0 until t for i++
for (i <- 1 to t) {
// assuming n,m and p are all on the same line
val Array(n,m,p) = lines.next.split(' ').map(_.toInt)
// or (0 until n).toList if you prefer
// not sure about the difference performance-wise
val players = List.range(0,n).map { j =>
val Array(name,pct,height) = lines.next.split(' ')
Player(name, pct.toInt, height.toInt)
}
val ret = solve(players,n,m,p)
print(s"Case #${i+1} : ")
ret.foreach(player => print(player.name+" "))
println
}
}