• Regan Heath (22/22) Aug 17 2005 import std.stdio;
• zwang (3/28) Aug 17 2005 The problem never occured to me because I usually write like this:
• Regan Heath (6/29) Aug 17 2005 Thanks. I'll probably change it to something like that.. I had recoded i...
• Walter (4/4) Aug 27 2005 These kinds of problems cannot be solved by juggling around the promotio...
• Regan Heath (14/18) Aug 28 2005 There appears to be no warning (when using -w) when comparing signed and...

"Regan Heath" <regan netwin.co.nz> writes:

import std.stdio;

void main()
{
	char[][] tmp;
	
	tmp ~= "1";
	tmp ~= "2";
	//add these, no problem
	//tmp ~= "3";
	//tmp ~= "4";
	//tmp ~= "5";
	
	for(int i = 0; i < tmp.length-3; i += 3)
	{
		writefln(tmp[i],",",tmp[i+1],",",tmp[i+2]);
	}
}

The code above causes an array bounds error. This occurs because  
tmp.length-3 == 4294967295 instead of -1.
There are no errors or warnings about comparing an int 'i' with a uint  
'tmp.length'.

Regan

zwang <nehzgnaw gmail.com> writes:

Regan Heath wrote:
 import std.stdio;
 
 void main()
 {
     char[][] tmp;
     
     tmp ~= "1";
     tmp ~= "2";
     //add these, no problem
     //tmp ~= "3";
     //tmp ~= "4";
     //tmp ~= "5";
     
     for(int i = 0; i < tmp.length-3; i += 3)
     {
         writefln(tmp[i],",",tmp[i+1],",",tmp[i+2]);
     }
 }
 
 The code above causes an array bounds error. This occurs because  
 tmp.length-3 == 4294967295 instead of -1.
 There are no errors or warnings about comparing an int 'i' with a uint  
 'tmp.length'.
 
 Regan

The problem never occured to me because I usually write like this:

for(int i = 0; i+3 < tmp.length; i += 3)

"Regan Heath" <regan netwin.co.nz> writes:

On Wed, 17 Aug 2005 20:40:23 +0800, zwang <nehzgnaw gmail.com> wrote:
 Regan Heath wrote:
 import std.stdio;
  void main()
 {
     char[][] tmp;
         tmp ~= "1";
     tmp ~= "2";
     //add these, no problem
     //tmp ~= "3";
     //tmp ~= "4";
     //tmp ~= "5";
         for(int i = 0; i < tmp.length-3; i += 3)
     {
         writefln(tmp[i],",",tmp[i+1],",",tmp[i+2]);
     }
 }
  The code above causes an array bounds error. This occurs because   
 tmp.length-3 == 4294967295 instead of -1.
 There are no errors or warnings about comparing an int 'i' with a uint   
 'tmp.length'.
  Regan

 The problem never occured to me because I usually write like this:

 for(int i = 0; i+3 < tmp.length; i += 3)

Thanks. I'll probably change it to something like that.. I had recoded it  
to:

int len = tmp.length;
for(int i = 0; i < len-3; i += 3)

Regan

"Walter" <newshound digitalmars.com> writes:

These kinds of problems cannot be solved by juggling around the promotion
rules, conversion rules, etc. They just shift and manifest themselves in
some other way. The only way to deal with it is to be wary of code that
might cross 0 or int.max boundaries.

"Regan Heath" <regan netwin.co.nz> writes:

On Sat, 27 Aug 2005 14:33:57 -0700, Walter <newshound digitalmars.com>  
wrote:
 These kinds of problems cannot be solved by juggling around the promotion
 rules, conversion rules, etc. They just shift and manifest themselves in
 some other way. The only way to deal with it is to be wary of code that
 might cross 0 or int.max boundaries.

There appears to be no warning (when using -w) when comparing signed and  
unsigned, eg.

void main()
{
	uint i = 4;
	int j = 6;	
	if (i < j) {}
}

C:\Library\D\src\temp>dmd -w signed.d
C:\Library\D\dmd\bin\..\..\dm\bin\link.exe signed,,,user32+kernel32/noi;

Perhaps you could add one?

Regan