Constructs

[Landrew]

There is a new book-ish like entity that is freely available on the web:

"Constructs of the C++ Proramming Language"

The book is intended to serve as a light-weight reference for developers
with modest experience in C++.

Enjoy,
Landrew

[Landrew]

Re: Constructs

Doh!

To be found at www.landrew.com


"Landrew" <news04@landrew .com> wrote in message
news:tdCdnZBBmp tw5ybcRVn-uw@speakeasy.ne t...[color=blue]
> There is a new book-ish like entity that is freely available on the web:
>
> "Constructs of the C++ Proramming Language"
>
> The book is intended to serve as a light-weight reference for developers
> with modest experience in C++.
>
> Enjoy,
> Landrew
>[/color]

[Niels Dekker - no reply address]

Re: Constructs

Landrew wrote:[color=blue]
>
> "Constructs of the C++ Proramming Language"
>
> To be found at www.landrew.com[/color]

Cool! Thanks!

https://www.landrew.com/cgi-bin/Via/Eval.pl?site=landrew&page=Article&article=01+Strings&path=/Languages/C%2B%2B/Constructs/Strings

says:[color=blue]
>
> void process()
> {
> char s[100] = "hop on!";
> }
>
> The first seven positions in s are set to 'h', 'o', 'p', ' '
> (space), 'o', 'n', '!'. The eigth position is set to a special
> end of string marker, called the null character. The null
> character is denoted by '\0' when it explicitly appears in code.[/color]

s[8] to s[99] are set to a null character as well.

[color=blue]
> Thus the code above has the same effect as the following:
>
> void process()
> {
> char s[100];
>
> s[0] = 'h';
> s[1] = 'o';
> s[2] = 'p';
> s[3] = ' ';
> s[4] = 'o';
> s[5] = 'n';
> s[6] = '!';
> s[7] = '\0'; // end of string marker (null character)
> }[/color]

This version will leave s[8] to s[99] uninitialized. Also it might take
less memory during runtime, because it won't store this literal string,
"hop on!".


Regards,

Niels Dekker

http://www.xs4all.nl/~nd/dekkerware

[Landrew]

Re: Constructs

> s[8] to s[99] are set to a null character as well.

interesting. are you certain about that? i would have thought it would be
true for global variables, but not for local variables.

just as this initializes x to zero

----
int x;

int main()
{
...
}
----

but this does not

----
int main()
{
int x;

...
}
----

at least that is what i thought :)

landrew


"Niels Dekker - no reply address" <unknown@this.i s.invalid> wrote in message
news:41BC6417.2 4B2D4E6@this.is .invalid...[color=blue]
> Landrew wrote:[color=green]
>>
>> "Constructs of the C++ Proramming Language"
>>
>> To be found at www.landrew.com[/color]
>
> Cool! Thanks!
>
>
> https://www.landrew.com/cgi-bin/Via/...tructs/Strings
> says:[color=green]
>>
>> void process()
>> {
>> char s[100] = "hop on!";
>> }
>>
>> The first seven positions in s are set to 'h', 'o', 'p', ' '
>> (space), 'o', 'n', '!'. The eigth position is set to a special
>> end of string marker, called the null character. The null
>> character is denoted by '\0' when it explicitly appears in code.[/color]
>
> s[8] to s[99] are set to a null character as well.
>
>[color=green]
>> Thus the code above has the same effect as the following:
>>
>> void process()
>> {
>> char s[100];
>>
>> s[0] = 'h';
>> s[1] = 'o';
>> s[2] = 'p';
>> s[3] = ' ';
>> s[4] = 'o';
>> s[5] = 'n';
>> s[6] = '!';
>> s[7] = '\0'; // end of string marker (null character)
>> }[/color]
>
> This version will leave s[8] to s[99] uninitialized. Also it might take
> less memory during runtime, because it won't store this literal string,
> "hop on!".
>
>
> Regards,
>
> Niels Dekker
> http://www.xs4all.nl/~nd/dekkerware[/color]

[Niels Dekker - no reply address]

Re: Constructs

www.landrew.com says:[color=blue]
>
> void process()
> {
> char s[100] = "hop on!";
> }
>
> The first seven positions in s are set to 'h', 'o', 'p', ' '
> (space), 'o', 'n', '!'. The eigth position is set to a special
> end of string marker, called the null character. The null
> character is denoted by '\0' when it explicitly appears in code.[/color]

And I commented:[color=blue]
>
> s[8] to s[99] are set to a null character as well.[/color]

Landrew wrote:[color=blue]
>
> interesting. are you certain about that?[/color]

Well... home.tiscalinet .ch/t_wolf/tw/c/string_init.htm l says:[color=blue]
>
> yes, if a string literal in an initializer contains less characters
> than the array has elements, the remaining elements are set to 0.[/color]

I guess the same holds in C++.


Regards,

Niels Dekker

http://www.xs4all.nl/~nd/dekkerware