Search Results

Search found 1100 results on 44 pages for 'bitwise operators'.

Page 27/44 | < Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >

  • How can I solve NP complete problems in erlang?

    - by Yadira Suazo
    Hi, I already have my operators for, by example, eat banana problem [#op{ action = [climb, on, {object}], preconds = [[at, {place}, {object}], [at, {place}, me], [on, floor, me], [on, floor, {object}], [large, {object}]], add_list = [[on, {object}, me]], del_list = [[on, floor, me]] }, But how can I use it in the function solve(Problem, depth_first, []). And depth_first (Problem, Start) - search_tree(Problem, container.stack, Start).

    Read the article

  • Does Java have a .new operator?

    - by chickeninabiscuit
    I came across this code today whilst reading Accelerated GWT (Gupta) - page 151. public static void getListOfBooks(String category, BookStore bookStore) { serviceInstance.getBooks(category, bookStore.new BookListUpdaterCallback()); } public static void storeOrder(List books, String userName, BookStore bookStore) { serviceInstance.storeOrder(books, userName, bookStore.new StoreOrderCallback()); } What are those new operators doing there? I've never seen such syntax, can anyone explain?

    Read the article

  • Assign to a slice of a Python list from a lambda

    - by Bushman
    I know that there are certain "special" methods of various objects that represent operations that would normally be performed with operators (i.e. int.__add__ for +, object.__eq__ for ==, etc.), and that one of them is list.__setitem, which can assign a value to a list element. However, I need a function that can assign a list into a slice of another list. Basically, I'm looking for the expression equivalent of some_list[2:4] = [2, 3].

    Read the article

  • Helping linqtosql datacontext use implicit conversion between varchar column in the database and tab

    - by user213256
    I am creating an mssql database table, "Orders", that will contain a varchar(50) field, "Value" containing a string that represents a slightly complex data type, "OrderValue". I am using a linqtosql datacontext class, which automatically types the "Value" column as a string. I gave the "OrderValue" class implicit conversion operators to and from a string, so I can easily use implicit conversion with the linqtosql classes like this: // get an order from the orders table MyDataContext db = new MyDataContext(); Order order = db.Orders(o => o.id == 1); // use implicit converstion to turn the string representation of the order // value into the complex data type. OrderValue value = order.Value; // adjust one of the fields in the complex data type value.Shipping += 10; // use implicit conversion to store the string representation of the complex // data type back in the linqtosql order object order.Value = value; // save changes db.SubmitChanges(); However, I would really like to be able to tell the linqtosql class to type this field as "OrderValue" rather than as "string". Then I would be able to avoid complex code and re-write the above as: // get an order from the orders table MyDataContext db = new MyDataContext(); Order order = db.Orders(o => o.id == 1); // The Value field is already typed as the "OrderValue" type rather than as string. // When a string value was read from the database table, it was implicity converted // to "OrderValue" type. order.Value.Shipping += 10; // save changes db.SubmitChanges(); In order to achieve this desired goal, I looked at the datacontext designer and selected the "Value" field of the "Order" table. Then, in properties, I changed "Type" to "global::MyApplication.OrderValue". The "Server Data Type" property was left as "VarChar(50) NOT NULL" The project built without errors. However, when reading from the database table, I was presented with the following error message: Could not convert from type 'System.String' to type 'MyApplication.OrderValue'. at System.Data.Linq.DBConvert.ChangeType(Object value, Type type) at Read_Order(ObjectMaterializer1 ) at System.Data.Linq.SqlClient.ObjectReaderCompiler.ObjectReader2.MoveNext() at System.Linq.Buffer1..ctor(IEnumerable1 source) at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source) at Example.OrdersProvider.GetOrders() at ... etc From the stack trace, I believe this error is happening while reading the data from the table. When presented with converting a string to my custom data type, even though the implicit conversion operators are present, the DBConvert class gets confused and throws an error. Is there anything I can do to help it not get confused and do the implicit conversion? Thanks in advance, and apologies if I have posted in the wrong forum. cheers / Ben

    Read the article

  • How Does iPhone Visual Voicemail Work From An Operator Perspective?

    - by Jasarien
    I'm hoping there are some Cell Phone Operator gurus here today. Would anyone be able to explain how Operators achieve the Visual Voicemail feature on the iPhone (and I assume other newer smart phones)? If a new cell phone operator that distributed SIM cards wanted to utilise the visual voicemail feature on unlocked iPhone's what services need to be in place to be able to support it? Is there an open spec or is it completely proprietary?

    Read the article

  • What is an overloaded operator in c++?

    - by Jeff
    I realize this is a basic question but I have searched online, been to cplusplus.com, read through my book, and I can't seem to grasp the concept of overloaded operators. A specific example from cplusplus.com is: // vectors: overloading operators example #include <iostream> using namespace std; class CVector { public: int x,y; CVector () {}; CVector (int,int); CVector operator + (CVector); }; CVector::CVector (int a, int b) { x = a; y = b; } CVector CVector::operator+ (CVector param) { CVector temp; temp.x = x + param.x; temp.y = y + param.y; return (temp); } int main () { CVector a (3,1); CVector b (1,2); CVector c; c = a + b; cout << c.x << "," << c.y; return 0; } from http://www.cplusplus.com/doc/tutorial/classes2/ but reading through it I'm still not understanding them at all. I just need a basic example of the point of the overloaded operator (which I assume is the "CVector CVector::operator+ (CVector param)"). There's also this example from wikipedia: Time operator+(const Time& lhs, const Time& rhs) { Time temp = lhs; temp.seconds += rhs.seconds; if (temp.seconds >= 60) { temp.seconds -= 60; temp.minutes++; } temp.minutes += rhs.minutes; if (temp.minutes >= 60) { temp.minutes -= 60; temp.hours++; } temp.hours += rhs.hours; return temp; } from "http://en.wikipedia.org/wiki/Operator_overloading" The current assignment I'm working on I need to overload a ++ and a -- operator. Thanks in advance for the information and sorry about the somewhat vague question, unfortunately I'm just not sure on it at all.

    Read the article

  • When would JavaScript == make more sense than ===?

    - by bryantsai
    As 359494 indicates they are basically identical except '===' also ensures type equality and hence '==' might perform type conversion. In Douglas Crockford's JavaScript: The Good Parts, it is advised to always avoid '=='. However, I'm wondering what the original thought of designing two set of equality operators was. Have you seen any situation that using '==' actually is more suitable than using '==='?

    Read the article

  • Are there any LIDIL documentation?

    - by Eskat0n
    As a part of my univercity work I have to write a program in LIDIL and describe its operators and functions but I can't find any documentation on this language. Naturally I've tried to google but nothing found on the first 40 pages of search results so I gave up. SO is my last hope. Any trace of info about LIDIL is fine for me.

    Read the article

  • Why doesn't SQL LIKE work in Microsoft Access?

    - by poo
    I want to my make a search-statement and query things like this select * from table where col like '%vkvk%' But with trial and error I've come to the conclusion that access doesn't work with LIKE or wildcard operators. Does anybody have some other solutions because I ain't so in to access actually, so I really don't know.

    Read the article

  • Constructing an if statement from the client data in python

    - by Vishal
    Hi, I need to construct an if statement from the data coming from the client as below: conditions: condition1, condition2, condition3, condition4 logical operators: lo1, lo2, lo3 (Possible values: "and" "or") Eg. if condition1 lo1 condition2 lo3 condition4: # Do something I can think of eval/exec but not sure how safe they are! Any better approach or alternative? Appreciate your responses :) PS: Client-side: Flex, Server-side: Python, over internet Thanks

    Read the article

  • Loosely coupled implicit conversion

    - by ltjax
    Implicit conversion can be really useful when types are semantically equivalent. For example, imagine two libraries that implement a type identically, but in different namespaces. Or just a type that is mostly identical, except for some semantic-sugar here and there. Now you cannot pass one type into a function (in one of those libraries) that was designed to use the other, unless that function is a template. If it's not, you have to somehow convert one type into the other. This should be trivial (or otherwise the types are not so identical after-all!) but calling the conversion explicitly bloats your code with mostly meaningless function-calls. While such conversion functions might actually copy some values around, they essentially do nothing from a high-level "programmers" point-of-view. Implicit conversion constructors and operators could obviously help, but they introduce coupling, so that one of those types has to know about the other. Usually, at least when dealing with libraries, that is not the case, because the presence of one of those types makes the other one redundant. Also, you cannot always change libraries. Now I see two options on how to make implicit conversion work in user-code: The first would be to provide a proxy-type, that implements conversion-operators and conversion-constructors (and assignments) for all the involved types, and always use that. The second requires a minimal change to the libraries, but allows great flexibility: Add a conversion-constructor for each involved type that can be externally optionally enabled. For example, for a type A add a constructor: template <class T> A( const T& src, typename boost::enable_if<conversion_enabled<T,A>>::type* ignore=0 ) { *this = convert(src); } and a template template <class X, class Y> struct conversion_enabled : public boost::mpl::false_ {}; that disables the implicit conversion by default. Then to enable conversion between two types, specialize the template: template <> struct conversion_enabled<OtherA, A> : public boost::mpl::true_ {}; and implement a convert function that can be found through ADL. I would personally prefer to use the second variant, unless there are strong arguments against it. Now to the actual question(s): What's the preferred way to associate types for implicit conversion? Are my suggestions good ideas? Are there any downsides to either approach? Is allowing conversions like that dangerous? Should library implementers in-general supply the second method when it's likely that their type will be replicated in software they are most likely beeing used with (I'm thinking of 3d-rendering middle-ware here, where most of those packages implement a 3D vector).

    Read the article

  • operator overloading c++

    - by segfault
    When overloading operators, is it necessary to overload = <= and !=? It seems like it would be smart for c++ to call !operator= for !=, ! for operator<= and !< for operator=. Is that the case, or is it necessary to overload every function?

    Read the article

  • Easiest way to calculate amount of even numbers in given range

    - by Fdr
    What is the simplest way to calculate the amount of even numbers in a range of unsigned integers? An example: if range is [0...4] then the answer is 3 (0,2,4) I'm having hard time to think of any simple way. The only solution I came up involved couple of if-statements. Is there a simple line of code that can do this without if-statements or ternary operators?

    Read the article

  • Parsing Range Expressions

    - by sameer karjatkar
    I have a string (R(46 - 9900)) AND ( NOT (R(48 - 9900))) where R denotes Range . If you evaluate the expression it results in R(46-47) , considering the logical operators (AND,NOT). I have a requirement where I need to parse such a string and evaluate it to a correct result . I have to use C++ as a programming tool to achieve this result . Can anyone suggest a few guide lines as to how do I proceed on this ?

    Read the article

  • What's the purpose of the rotate instructions (ROL, RCL on x86) ?

    - by lgratian
    I always wondered what's the purpose of the rotate instructions some CPUs have (ROL, RCL on x86, for example). What kind of software makes use of these instructions? I first thought they may be used for encryption/computing hash codes, but these libraries are written usually in C, which doesn't have operators that map to these instructions. Has anybody found an use for them? Why where they added to the instructions set?

    Read the article

  • Python bitoperators

    - by Neelima
    What do the bit operators like AND(&),OR(|),XOR(^) in python do behind the screen? What do they calculate? I cannot understand the results they give when used in a program? 30&45 yields 12. How can we relate these three? 30|45 yields 63. How are these three related? Please answer this...

    Read the article

  • What are some tricks I can use with macros?

    - by Sasha
    In our legacy code, as well as our modern code, we use macros to perform nifty solutions like code generations, etc. And we make use of both the # and ## operators. I am curious how other developers use macros to do cool things, if they use them at all.

    Read the article

  • C++ code generation with Python

    - by norapinephrine
    Can anyone point me to some documentation on how to write scripts in Python (or Perl or any other Linux friendly script language) that generate C++ code from XML or py files from the command line. I'd like to be able to write up some xml files and then run a shell command that reads these files and generates .h files with fully inlined functions, e.g. streaming operators, constructors, etc.

    Read the article

  • Multiple data centers and HTTP traffic: DNS Round Robin is the ONLY way to assure instant fail-over?

    - by vmiazzo
    Hi, Multiple A records pointing to the same domain seem to be used almost exclusively to implement DNS Round Robin as a cheap load balancing technique. The usual warning against DNS RR is that it is not good for high availability. When 1 IP goes down clients will continue to use it for minutes. A load balancer is often suggested as a better choice. Both claims are not completely true: When the traffic is HTTP then, most of the HTML browsers are able to automatically try the next A record if the previous is down, without a new DNS look-up. Read here chapter 3.1 and here. When multiple data centers are involved then, DNS RR is the only option to distribute traffic across them. So, is it true that, with multiple data centers and HTTP traffic, the use of DNS RR is the ONLY way to assure instant fail-over when one data center goes down? Thanks, Valentino Edit: Off course each data center has a local Load Balancer with hot spare. It's OK to sacrifice session affinity for an instant fail-over. AFAIK the only way for a DNS to suggest a data center instead of another is to reply with just the IP (or IPs) associated to that data center. If the data center becomes unreachable then all those IP are also unreachables. This means that, even if smart HTML browsers are able to instantly try another A record , all the attempts will fail until the local cache entry expires and a new DNS lookup is done, fetching the new working IPs (I assume DNS automatically suggests to a new data center when one fail). So, "smart DNS" cannot assure instant fail-over. Conversely a DNS round-robin permits it. When one data center fail, the smart HTML browsers (most of them) instantly try the other cached A records jumping to another (working) data center. So, DNS round-robin doesn't assure session affinity or the lowest RTT but seems to be the only way to assure instant fail-over when the clients are "smart" HTML browsers. Edit 2: Some people suggest TCP Anycast as a definitive solution. In this paper (chapter 6) is explained that Anycast fail-over is related to BGP convergence. For this reason Anycast can employ from 15 minutes to 20 seconds to complete. 20 seconds are possible on networks where the topology was optimized for this. Probably just CDN operators can grant such fast fail-overs. Edit 3:* I did some DNS look-ups and traceroutes (maybe some expert can double check) and: The only CDN using TCP Anycast seems to be CacheFly, other operators like CDN networks and BitGravity use CacheFly. Seems that their edges cannot be used as reverse proxies. Therefore, they cannot be used to grant instant failover. Akamai and LimeLight seems to use geo-aware DNS. But! They return multiple A records. From traceroutes seems that the returned IPs are on the same data center. So, I'm puzzled on how they can offer a 100% SLA when one data center goes down.

    Read the article

< Previous Page | 23 24 25 26 27 28 29 30 31 32 33 34  | Next Page >