Question

What is the preferred and best way in C++ to do this: Split the letters of the alphabeth into 7 groups so I can later ask if a char is in group 1, 3 or 4 etc… ? I can of course think of several ways of doing this myself but I want to know the standard and stick with it when doing this kinda stuff.

0
AEIOUHWY
1
BFPV
2
CGJKQSXZ
3
DT
4
MN
5
L

6
R

Answer 1

Create a lookup table.

int lookup[26] = { 0, 1, 2, 3, 0, 1, 2, 0 .... whatever };

inline int getgroup(char c)
{
    return lookup[tolower(c) - 'a'];
}

call it this way

char myc = 'M';
int grp = lookup(myc);

Error checks omitted for brevity.

Of course, depending on what the 7 groups represent , you can make enums instead of using 0, 1, 2 etc.