Retrieve the length of an int
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I have a string of text displaying the size of a file (in bytes) in the form "File Size: %d bytes" (where %d is the file size) and I would like to allocate enough memory whatever the file size. --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
Perspx wrote:
I have a string of text displaying the size of a file (in bytes) in the form "File Size: %d bytes" (where %d is the file size) and I would like to allocate enough memory whatever the file size.
DWORD dwFileSize = 123456;
char s[28];
sprintf(s, "File Size: %lu bytes", dwFileSize);
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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That's bad programming and a waste of resources. --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
Perspx wrote:
That's bad programming and a waste of resources.
:laugh:
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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If I have an integer value, and I want to write its value into a string, how do I work out how many characters the integer will take up? For example, if I have the number 100, and I want to put it into a string using sprintf, how do I dynamically work out how many characters the number will take up (in this case 3)? Thanks for your help! --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
. I leave you as an exercise the extension to
n<=0.//prerequisite:
n>0
int howmanychars(int n)
{
return (int)log10(n) + 1;
}BTW of course you don't need it :-D
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
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Perspx wrote:
That's bad programming and a waste of resources.
:laugh:
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
You can laugh but I bet that the reason that most Microsoft programs are slow and clunky is because the programmers who write them do bad programming techniques such as that.. and it doesn't matter for that particular example, as that only wastes 19 bytes at the maximum.. but if you apply that technique for other data allocation, then you could waste a lot more which makes your application unreliable and not perform so well.. --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
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That's bad programming and a waste of resources. --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
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You can laugh but I bet that the reason that most Microsoft programs are slow and clunky is because the programmers who write them do bad programming techniques such as that.. and it doesn't matter for that particular example, as that only wastes 19 bytes at the maximum.. but if you apply that technique for other data allocation, then you could waste a lot more which makes your application unreliable and not perform so well.. --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
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. I leave you as an exercise the extension to
n<=0.//prerequisite:
n>0
int howmanychars(int n)
{
return (int)log10(n) + 1;
}BTW of course you don't need it :-D
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
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Perspx wrote:
That's bad programming and a waste of resources.
:-D
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
Is that a laugh at me or in agreement? --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
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Perspx wrote:
I have a string of text displaying the size of a file (in bytes) in the form "File Size: %d bytes" (where %d is the file size) and I would like to allocate enough memory whatever the file size.
DWORD dwFileSize = 123456;
char s[28];
sprintf(s, "File Size: %lu bytes", dwFileSize);
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Thank you --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
Please note: I gave you the function only for informative pourposes (an academic exercise): you really don't need it. Moreover it will slow down your code. BTW: Think a bit before giving judge on programmers slowness, with David Crow you surely miss the target. :)
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
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Please note: I gave you the function only for informative pourposes (an academic exercise): you really don't need it. Moreover it will slow down your code. BTW: Think a bit before giving judge on programmers slowness, with David Crow you surely miss the target. :)
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
Yeah I know.. I'm not even a professional programmer :p but I really hate Windows programs which are really slow and clunky and don't manage resources well.. I'm not having a go at him, I'm grateful for the advice from him and everyone.. I'm just sure that there must be an efficient way of doing this and throwing memory away unnecessarily is a bit of a waste.. Don't you agree? --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
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Please note: I gave you the function only for informative pourposes (an academic exercise): you really don't need it. Moreover it will slow down your code. BTW: Think a bit before giving judge on programmers slowness, with David Crow you surely miss the target. :)
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
CPallini wrote:
hink a bit before giving judge on programmers slowness, with David Crow you surely miss the target.
Yep, that's the least we can say. :cool:
Don't follow any man spiritually, don't do anything that will get you in sh*t if god is real - Bradml[^]
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To solve that problem mathematically: take the logarithm to base 10 (double log10(double))and add 1. Else you can format it into a CString and check that length. Greetings, Martin edit: sorry, used the wrong log function (base e instead of base 10) -- modified at 10:22 Friday 3rd August, 2007
m.dietz wrote:
To solve that problem mathematically: take the logarithm to base 10 (double log10(double))and add 1.
First make sure the value is greater than zero. :)
m.dietz wrote:
Else you can format it into a CString and check that length.
the above works anyway. :-D
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler. -- Alfonso the Wise, 13th Century King of Castile.
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Yeah I know.. I'm not even a professional programmer :p but I really hate Windows programs which are really slow and clunky and don't manage resources well.. I'm not having a go at him, I'm grateful for the advice from him and everyone.. I'm just sure that there must be an efficient way of doing this and throwing memory away unnecessarily is a bit of a waste.. Don't you agree? --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
Perspx wrote:
...don't manage resources well
Don't forget, memory is not the only resource a computer has. Sounds to me like you're wasting the CPU time (another resource) in order to save a few bytes of memory. It's hard to imagine a case where those few bytes would ever matter. There's also the factor of code complexity -- sounds like you're making your code more complex than it needs to be. Since you're calculating size, I'd guess you're going to be allocating memory dynamically through malloc or new[] etc. Those schemes will add their own overhead which will swamp the few bytes you're aiming to save.
Perspx wrote:
Don't you agree?
In principal, yes, don't waste resources. However, I think you're going overboard in this case (the other posts seem to agree).
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You can laugh but I bet that the reason that most Microsoft programs are slow and clunky is because the programmers who write them do bad programming techniques such as that.. and it doesn't matter for that particular example, as that only wastes 19 bytes at the maximum.. but if you apply that technique for other data allocation, then you could waste a lot more which makes your application unreliable and not perform so well.. --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates
Perspx wrote:
I bet that the reason that most Microsoft programs are slow and clunky...
I highly doubt that. Reserving 1 byte or 20 bytes from the stack will make no noticeable difference in your code's execution time, but using the
log10()function and asking the memory manager for countless small amounts of memory will. Consider the following:for (int x = 0; x < nFileCount; x++)
{
int nLength = (int) (log10(dwFileSize) + 1.0);
char *s = new char[18 + nLength];
sprintf(s, "File Size: %lu bytes", dwFileSize);
delete [] s;
}compared to:
char s[28];
for (int x = 0; x < nFileCount; x++)
{
sprintf(s, "File Size: %lu bytes", dwFileSize);
}
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Perspx wrote:
...don't manage resources well
Don't forget, memory is not the only resource a computer has. Sounds to me like you're wasting the CPU time (another resource) in order to save a few bytes of memory. It's hard to imagine a case where those few bytes would ever matter. There's also the factor of code complexity -- sounds like you're making your code more complex than it needs to be. Since you're calculating size, I'd guess you're going to be allocating memory dynamically through malloc or new[] etc. Those schemes will add their own overhead which will swamp the few bytes you're aiming to save.
Perspx wrote:
Don't you agree?
In principal, yes, don't waste resources. However, I think you're going overboard in this case (the other posts seem to agree).
Ok yes I see what you are all saying.. Thanks everyone --PerspX
"Nowadays, security guys break the Mac every single day. Every single day, they come out with a total exploit, your machine can be taken over totally. I dare anybody to do that once a month on the Windows machine." - Bill Gates