char* line[255];
....
line[0] = '1'; // filled char by char
....

char charCode = (char)line[i];
if (charCode == 't' || charCode == 'n' || charCode == ',' || charCode == ' ')
{
      // do someting
}

warning: cast from pointer to integer of different size

line[0] = "1"; // filled char by char

line[0] = '1';

char* line[255];

char line[255];

char line[255];
....
line[0] = '1'; // filled char by char
....

char charCode = line[i];
if (charCode == 't' || charCode == 'n' || charCode == ',' || charCode == ' ')
{
      // do someting
}