So, as I understand it, the ADA programming language provides 2 remainder operators (along with a whole mess of allowable overloading for most operators). I'm having difficulty grasping the difference between the 2 remainder operators. I looked over this WikiBooks page I came across, but I don't think I'm making the light bulb turn on yet.
WikiBooks ADA Operators
Can anyone explain this a little better to me?
Difference in ADA Remainder Operators?
Page 1 of 12 Replies  1316 Views  Last Post: 20 November 2013  04:59 AM
Replies To: Difference in ADA Remainder Operators?
#2
Re: Difference in ADA Remainder Operators?
Posted 18 November 2013  01:48 PM
A mod B and A rem B are the same for positive integers A. The difference occurs when A is negative. mod will continue the looping pattern leaving only positive results. rem on the other hand will give negative results that are more of a reflection of the positive A's
for example
The reason for this is that mod technically returns a label representing a group of numbers. Every nth number is congruent (mod n). We say that 6,3,0,3,and 6 are congruent (mod 3) thus they belong to the same congruency class. It is somewhat convenient to chose 0 for the label of this class. Remainder is just the calculation of what is left over after integer division is performed. So a negative number will have a negative leftover.
for example
N 654321 0 1 2 3 4 5 6  N mod 3 0 1 2 0 1 2 0 1 2 0 1 2 0  N rem 3 021 021 0 1 2 0 1 2 0
The reason for this is that mod technically returns a label representing a group of numbers. Every nth number is congruent (mod n). We say that 6,3,0,3,and 6 are congruent (mod 3) thus they belong to the same congruency class. It is somewhat convenient to chose 0 for the label of this class. Remainder is just the calculation of what is left over after integer division is performed. So a negative number will have a negative leftover.
This post has been edited by mojo666: 18 November 2013  01:52 PM
#3
Re: Difference in ADA Remainder Operators?
Posted 20 November 2013  04:59 AM
Nice. Someone else knows the difference between reminder and modulus too.
I have been yelling about that on many Cforums, when people don't realize that "%" is reminder, not modulus.
In C (and C++) the "%" operator is called "mod" or "modulus", but the explanation is usually like "returns the remainder of expr1 divided by expr2".
I have been yelling about that on many Cforums, when people don't realize that "%" is reminder, not modulus.
In C (and C++) the "%" operator is called "mod" or "modulus", but the explanation is usually like "returns the remainder of expr1 divided by expr2".
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