illegal expression

[segfault]

I want to replace the last character in the string '012' by the value of i, which is a byte variable, but I'm getting an "illegal expression" error. Not sure why.

Code: Pascal  [Select][+][-]

1. var
2.   st  : string;
3.   i   : byte;
4. begin
5.   st := '012';
6.   i := 4;
7.   str(i, st[length(st)]);
8. end.

[howardpc]

Str takes a var string variable as its second parameter (not a character, as you tried to give it).

Code: Pascal  [Select][+][-]

1. var
2.   st, newSt: String;
3.   i: byte;
4. begin
5.   st := '012';
6.   i := 4;
7.   Str(i, newSt);
8.   st := Copy(st, 1, 2) + newSt;
9.   WriteLn('"',st,'"');
10.   ReadLn;
11. end.

[segfault]

D'oh!

Thanks. Actually the length of st varies so I need to modify your code slightly :

Code: Pascal  [Select][+][-]

1. var
2.   st,
3.   s   : string;
4.   i   : byte;
5. begin
6.   st := '0310';
7.   i := 4;
8.   str(i, s);
9.   st := copy(st, 1, length(st)-1) + s;
10.   writeln(st)
11. end.

[wp]

I get the impression that "i" should always represent a numeric digit ('0' to '9'). Then you can also do this:

Code: Pascal  [Select][+][-]

1.   st[Length(st)] := char(ord('0') + i);

If the input string is UTF8 encoded you must make sure that it has a single-byte code point at the end (i.e. < 128).