Re: ascii wilderness maps

From: Daniel A. Koepke (
Date: 11/16/99

On Tue, 16 Nov 1999, Jason Beeland wrote:

> ok, my thanks to everyone who pointed out that this was a c++ program rather
> than C.  I feel somewhat silly, though not too bad since i have actually not
> had any exposure to c++.  Using g++ resulted in many less errors, though
> unfortunately there were still a few.  Here is what g++ resulted in on
> compilation:
> ( The actual file i've been trying to compile can be found at
> )
> mapgen.c:135: warning: name lookup of `i' changed for new ANSI `for' scoping
> mapgen.c:94: warning:   using obsolete binding at `i'

Code like the following is ILLEGAL according to C++ standards:

    for (int i = 0; i < 10; i++) {

    table[i] = ...;

If 'i' really needs to live beyond the 'for' block, it should be changed
to read:

    int i;
    for (i = 0; i < 10; i++) {

    table[i] = ...;

This is because there was some initial confusion (or, perhaps,
disagreement) about what exactly the scope of a variable declared in a
'for' statement should be.  Many implementations had the declared variable
exist after the 'for' block.  The ANSI standard clarified matters, and
instituted some new scoping rules specifically for the 'for'
statement.  Specifically, a variable declared within the 'for' statement
inherets the scope of the 'for' block.  In other words, the variable does
not exist after the 'for' block.

> mapgen.c: In function `int WriteRoom(struct FILE *, int, int, int, int,
> struct FILE *)':
> mapgen.c:296: warning: implicit declaration of function `int ltoa(...)'

This function isn't part of the C++ libraries.  From its function name I
infer that it means to take a long integer and produce a string from
it.  It should be fairly easy to write a good version of this, but I'm in
a bit of a hurry, and since the code isn't too crucial, you can get away
with the ugly hack:

    char *ltoa (long l)
        static char retval[16];
        sprintf(retval, "%li", l);
        return (retval);

Please note that the return value is static, which means if you want to
keep it unchanged through multiple calls, you should copy the return value
using strcpy() or strdup() or something similar, i.e.,

    char *ptr = ltoa(4);
    char *ptr2 = ltoa(5);
    char *ptr3 = ltoa(6);
    printf("%s%s%s\n", ptr, ptr2, ptr3);

might lead you to believe your computer is possessed.


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