integer-division

问题 Is it safe to replace a/(b*c) with a/b/c when using integer-division on positive integers a,b,c , or am I at risk losing information? I did some random tests and couldn't find an example of a/(b*c) != a/b/c , so I'm pretty sure it's safe but not quite sure how to prove it. Thank you. 回答1: Mathematics As mathematical expressions, ⌊a/(bc)⌋ and ⌊⌊a/b⌋/c⌋ are equivalent whenever b is nonzero and c is a positive integer (and in particular for positive integers a , b , c ). The standard reference

问题 I am trying to convert a large number going in to Megabytes. I don't want decimals numeric function formatMB(required numeric num) output="false" { return arguments.num \ 1024 \ 1024; } It then throws an error How do I get around this? 回答1: You can't change the size of a Long, which is what CF uses for integers. So you'll need to BigInteger instead: numeric function formatMB(required numeric num) { var numberAsBigInteger = createObject("java", "java.math.BigInteger").init(javacast("string",

问题 This is (AFAIK) a specific question within this general topic. Here's the situation: I have an embedded system (a video game console) based on a 32-bit RISC microcontroller (a variant of NEC's V810). I want to write a fixed-point math library. I read this article, but the accompanying source code is written in 386 assembly, so it's neither directly usable nor easily modifiable. The V810 has built-in integer multiply/divide, but I want to use the 18.14 format mentioned in the above article.

问题 Please forgive my programming knowledge. I know this is a simple thing, but I do not understand why result is always 0. Why decimal will be fine? int a = 100; int b = 200; decimal c = (a / b) * 100; Many thanks. 回答1: Integer division always truncates the remainder. This is done at the time that the number is divided, not when it's assigned to the variable (as I'm guessing you assumed). decimal c = ((decimal)a / b) * 100; 回答2: The value a/b will return 0 always since they are integers. So when

问题 As far as I know most compilers will do fast division by multiplying and then bit shifting to the right. For instance, if you check this SO thread it says that when you ask the Microsoft compiler to do division by 10 it will multiply the dividend by 0x1999999A (which is 2^32/10) and then divide the result by 2^32 (using 32 shifts to the right). (Editor's note: that linked answer was wrong until. Compilers don't do that because it's not exact for all inputs. Compilers do multiply and shift,

问题 I'm working on Cortex-A8 and Cortex-A9 in particular. I know that some architectures don't come with integer division, but what is the best way to do it other than convert to float, divide, convert to integer? Or is that indeed the best solution? Cheers! = ) 回答1: The compiler normally includes a divide in its library, gcclib for example I have extracted them from gcc and use them directly: https://github.com/dwelch67/stm32vld/ then stm32f4d/adventure/gcclib going to float and back is probably

问题 How could I go about finding the division remainder of a number in Python? For example: If the number is 26 and divided number is 7, then the division remainder is 5. (since 7+7+7=21 and 26-21=5.) 回答1: you are looking for the modulo operator: a % b for example: 26 % 7 Of course, maybe they wanted you to implement it yourself, which wouldn't be too difficult either. 回答2: The remainder of a division can be discovered using the operator % : >>> 26%7 5 In case you need both the quotient and the

问题 For example: 9 / 5 #=> 1 but I expected 1.8 . How can I get the correct decimal (non-integer) result? Why is it returning 1 at all? 回答1: It’s doing integer division. You can make one of the numbers a Float by adding .0 : 9.0 / 5 #=> 1.8 9 / 5.0 #=> 1.8 回答2: It’s doing integer division. You can use to_f to force things into floating-point mode: 9.to_f / 5 #=> 1.8 9 / 5.to_f #=> 1.8 This also works if your values are variables instead of literals. Converting one value to a float is sufficient

问题 This question already has answers here : Int division: Why is the result of 1/3 == 0? (15 answers) Closed last year . int totalOptCount = 500; int totalRespCount=1500; float percentage =(float)(totalOptCount/totalRespCount); Why does this always return value 0.0? Also I want to format this into 00.00 format and convert into string? 回答1: Because the conversion to float happens after the division has been done. You need: float percentage = ((float) totalOptCount) / totalRespCount; You should be

问题 I had written a simple pascal triangle code in python but I am getting a error def factorial(n): c=1 re=1 for c in range(n): re = re * c; return(re) print "Enter how many rows of pascal triangle u want to show \n" n=input(); i=1 c=1 for i in range(n): for c in range(n-i-1): print "" for c in range(i): a = factorial(i); b = factorial(c); d = factorial(i-c); z = (a/(b*d)); print "%d" % z print "\n" ERROR: Traceback (most recent call last): File "/home/tanmaya/workspace/abc/a.py", line 19, in