c++ - Best way to compare input values to read values from files -

i relatively new c++ programming , have hit 1 of first major snags in of this..

i trying figure out how read value/character generic ".txt" file on notepad. comparison want determine whether or not read entire line, can't seem read single 1 or 2 digit number, got read whole line using { 'buffername'.getline(variable, size) } when try change 'size' specific number gives me comparison error saying invalid switch 'int' or 'char' (depending on how declare variable).

any appreciated. thanks

  int length = 2;   char * buffer;       ifstream is;   is.open ("test.txt", ios::binary );        // allocate memory:   buffer = new char [length];    // read 2 char   is.read (buffer,length);    //compare character , decide         delete[] buffer;   return 0;