You didn't initialize it to point to any memory, so as of right now it points to random arbitrary memory, and then you're trying to read into that memory, overwriting was was originally there and (hopefully) getting a segfault.
Also, never use char * for strings, especially for input - the issue is you would have to have a fixed size on the memory you initialize, and if the user inputs more than that fixed size you've got problems.
ifstream file;
char text[100]; // or a maximum size you would ever expect
file.open("file.txt");
while(file.good())
{
file >> text;
cout << text << endl;
}