Values of array randomly change - c++

Question

So I have a text file which has information about basketball players and it looks like this:
8
9 5 7 -5 13 -4 11
7 5 -3 12 -5 17 -3
25 7 12 -3 5 -5 7 -5 3
14 5 12 -3 10 -7 8
5 1 -40
33 5 15 -5 9 -3 8
11 5 -12 8 -5 12 -3
13 5 3 -4 25 -5 3
First integer in the first line shows how many players are there. In every other line the first integer is the number of the player, the second integer shows how many more integers there are in the line and each of the following integers shows if the player is playing (if the integer is positive) or sitting on the bench (if the number is negative).
I want to read the info to an array of structures which look like this:
struct player
{
int nr;
int k;
int bus[];
};
I've written a function to do so:
void skaitymas(int &n, player mas[])
{
ifstream duom("U1.txt");
duom >> n;
for (int i=0; i < n; i++) {
duom >> mas[i].nr >> mas[i].k;
for (int f=0; f < mas[i].k; f++) {
duom >> mas[i].bus[f];
}
}
}
When I run it the program seems to work, however the arrays of structures save unexpected values. After adding some cout commands in random places, I found out that it saves the correct values to the array the first time, first for loop loops, but after some iterations it changes the values of the previous arrays. For example, when i in the for loop equals 1 then mas[1].bus[0] is saved to be -3, as it should be, however after i changes to 2, mas[1].bus[0] changes to 25.
I would appreciate it if you would help me to figure it out, why the numbers in the arrays change to other random numbers from the text file, even if I don't do anything to them.

Answer 1

There are several problems with your code. The most obvious is
that int bus[] declares a variable with an incomplete type,
and it is illegal in C++ to declare a member variable with an
incomplete type. Unless your compiler is seriously broken, this
shouldn't compile; at the very latest, you should get an error
when you write mas[i], since there is no possible way of doing
pointer arithmetic on a pointer to an incomplete type. The way
to declare your class is:
struct Player
{
int nr;
std::vector<int> bus;
};
Once you do this, you should be able to compile. Still, it's
very poor C++ to read in counts of the following elements. The
correct way of doing this would be to drop the counts in the
file: the number of lines is the number of players, and the
number of integers following the first in the line is the number
of integers following the first in the line. If you do this,
you end up with something like:
std::vector<Player> skaitymas()
{
std::ifsteram duom( "U1.txt" );
if ( !duom.is_open() ) {
// Some sort of error handling, maybe an exception.
}
std::vector<Player> results;
std::string line;
while ( std::getline( duom, line ) ) {
std::istringstream s( line );
int nr;
s >> nr;
if ( !s ) {
// Format error...
}
results.push_back(Player{ nr });
while ( s >> nr ) {
results.back().bus.push_back( nr );
}
}
return results;
}
Everything is done dynamically (which is very simple in C++).