sdafjsdhjk
int
(int)*      -> (semmi) int  intint  intintintint
(int)+      ->         int  intint  intintintint
(k1|k2)
(foo|bar)   -> foo     bar
[abc]       -> a    b      c
[0-9]
[a-z]
[a-z0-9]
[a-z0-9A-Z]
.           -> bármi (kivéve \n)
\n          -> newline (új sor)
\t          -> tab
\\          -> \
\.
"[.]"
\[\.\]
"int"
"a[b"
a\[b
a\"b
"a\"b"      -> a"b
abc[de]?fg  -> abcfg    abcdfg  abcefg
[1234567890]
[qwertyuiopasdfghjklzxcvbnm]


1a
    (0|1|2|3|4|5|6|7|8|9)
    [1234567890]
    [0-9]

    ([0-9])*
    [0-9]*
    [0-9]+
    a[0-9]*
    a[0-9]+
1b
    0|[1-9][0-9]*
    [0-9]|[1-9][0-9]*
    0|[1-9][0-9]+       <---- nem jó
    [0-9]|[1-9][0-9]+
1c
    (\+|\-)?{1a}
    [+-]{1a}
    [+- ]{1a}   <------------- ez nem az!!!
    [+-]?{1a}
    [\+\-]{1a}
    [+-]{1b}
1d
    {1a}\.{1a}          0.34
                        .34
                        4.
    {1a}"."{1a}|{1a}"."|"."{1a}
    {1a}?"."{1a}?     <---------   .
    {1c}\.{1a}
                        1.0000000
                        1.0


2a
    [a-zA-Z][a-zA-Z_0-9]*
    [a-Z]    <--------- ez nem az!
    [A-z]

2b
    //.*
    //.*\n
2e
    [ \t\n]*

2d
    \".*\"    <--------- így nem jó, mert """
2c
    erre figyelni: /* */ */