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  • Translation of a RoR view to Java

    - by mnml
    Hi, for some reasons I am trying to translate the following RoR view code to a GSP view: List<Object> objectscontains the data I want to display in 3 columns <% modulo_objects = @objects.length % 3 base = @objects.length / 3 base = base.ceil case modulo_objects when 0 cols = [base, base, base] when 1 cols = [base, base + 1, base] when 2 cols = [base + 1, base, base + 1] end counter = 0 %> <% 3.times do |i| %> <td width="220" align="center" style="padding-right: 15px;"> <% cols[i].times do %> <h1><a href="/objects/show/<%= @objects[counter].urlname %>" ><%= @objects[counter].name %></a></h1> <% counter = counter + 1 %> <% end %> </td> <% end %> This is what I got so far: #{extends 'main.html' /} %{ modulo_objects = objects.size() % 3 base = objects.size() / 3 base = Math.ceil(base) if(modulo_objects == 0) cols = [base, base, base] else if(modulo_objects == 1) cols = [base, base + 1, base] else if(modulo_objects == 2) cols = [base + 1, base, base + 1] endif counter = 0 }% #{list items:1..3, as:'i'} <td width="220" align="center" style="padding-right: 15px;"> #{list items:cols[i]} <a href="@{Objects.show(objects.get(counter).name.replaceAll(" ", "-"))}" >${objects.get(counter).name}</a> %{ counter = counter + 1 }% #{/list} </td> #{/list} The idea is to keep the items organised in 3 columns like 1|0|1 4|5|4 or 5|4|5 for example, I don't really understand if #{list items:cols[i]} will reproduce ruby's cols[i].times do. So far the Java view is does not display more than two elements.

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  • Image re sizing not working after rotation in Html5 canvas

    - by Deepu the Don
    In my HTML 5 + Javascript application, we can drag, re size and rotate image in Html 5 canvas. But after doing rotation, re sizing is not working. (I think it i related to finding dx,dy,not sure). Please help me to fix the code given below. Thanks in advance. <!doctype html> <html> <head> <style> #canvas{ border:red dashed #ccc; } </style> <script type="text/javascript" src="http://code.jquery.com/jquery.min.js"></script> <script> $(function(){ var canvas=document.getElementById("canvas"),ctx=canvas.getContext("2d"),canvasOffset=$("#canvas").offset(); var offsetX=canvasOffset.left,offsetY=canvasOffset.top,startX,startY,isDown=false,pi2=Math.PI*2; var resizerRadius=8,rr=resizerRadius*resizerRadius,draggingResizer={x:0,y:0},imageX=50,imageY=50; var imageWidth,imageHeight,imageRight,imageBottom,draggingImage=false,startX,startY,doRotation=false; var r=0,rotImg = new Image(); rotImg.src="rotation.jpg"; var img=new Image(); img.onload=function(){ imageWidth=img.width; imageHeight=img.height; imageRight=imageX+imageWidth; imageBottom=imageY+imageHeight; w=img.width/2; h=img.height/2; draw(true,false); } img.src="https://dl.dropboxusercontent.com/u/139992952/stackoverflow/facesSmall.png"; function draw(withAnchors,withBorders){ ctx.fillStyle="black"; ctx.clearRect(0,0,canvas.width,canvas.height); ctx.save(); ctx.translate(imageX,imageY); ctx.translate(imageWidth/2,imageHeight/2); ctx.rotate(r); ctx.translate(-imageX,-imageY); ctx.translate(-imageWidth/2,-imageHeight/2); ctx.drawImage(img,0,0,img.width,img.height,imageX,imageY,imageWidth,imageHeight); ctx.restore(); if(withAnchors){ drawDragAnchor(imageX,imageY); drawDragAnchor(imageRight,imageY); drawDragAnchor(imageRight,imageBottom); drawDragAnchor(imageX,imageBottom); } if(withBorders){ ctx.save(); ctx.translate(imageX,imageY); ctx.translate(imageWidth/2,imageHeight/2); ctx.rotate(r); ctx.translate(-imageX,-imageY); ctx.translate(-imageWidth/2,-imageHeight/2); ctx.beginPath(); ctx.moveTo(imageX,imageY); ctx.lineTo(imageRight,imageY); ctx.lineTo(imageRight,imageBottom); ctx.lineTo(imageX,imageBottom); ctx.closePath(); ctx.stroke(); ctx.restore(); } ctx.fillStyle="blue"; ctx.save(); ctx.translate(imageX,imageY); ctx.translate(imageWidth/2,imageHeight/2); ctx.rotate(r); ctx.translate(-imageX,-imageY); ctx.translate(-imageWidth/2,-imageHeight/2); ctx.beginPath(); ctx.moveTo(imageRight+15,imageY-10); ctx.lineTo(imageRight+45,imageY-10); ctx.lineTo(imageRight+45,imageY+20); ctx.lineTo(imageRight+15,imageY+20); ctx.fill(); ctx.closePath(); ctx.restore(); } function drawDragAnchor(x,y){ ctx.save(); ctx.translate(imageX,imageY); ctx.translate(imageWidth/2,imageHeight/2); ctx.rotate(r); ctx.translate(-imageX,-imageY); ctx.translate(-imageWidth/2,-imageHeight/2); ctx.beginPath(); ctx.arc(x,y,resizerRadius,0,pi2,false); ctx.closePath(); ctx.fill(); ctx.restore(); } function anchorHitTest(x,y){ var dx,dy; dx=x-imageX; dy=y-imageY; if(dx*dx+dy*dy<=rr){ return(0); } // top-right dx=x-imageRight; dy=y-imageY; if(dx*dx+dy*dy<=rr){ return(1); } // bottom-right dx=x-imageRight; dy=y-imageBottom; if(dx*dx+dy*dy<=rr){ return(2); } // bottom-left dx=x-imageX; dy=y-imageBottom; if(dx*dx+dy*dy<=rr){ return(3); } return(-1); } function hitImage(x,y){ return(x>imageX && x<imageX+imageWidth && y>imageY && y<imageY+imageHeight); } function handleMouseDown(e){ startX=parseInt(e.clientX-offsetX); startY=parseInt(e.clientY-offsetY); draggingResizer= anchorHitTest(startX,startY); draggingImage= draggingResizer<0 && hitImage(startX,startY); doRotation = draggingResizer<0 && !draggingImage && ctx.isPointInPath(startX,startY); } function handleMouseUp(e){ draggingResizer=-1; draggingImage=false; doRotation=false; draw(true,false); } function handleMouseOut(e){ handleMouseUp(e); } function handleMouseMove(e){ mouseX=parseInt(e.clientX-offsetX); mouseY=parseInt(e.clientY-offsetY); if(draggingResizer>-1){ switch(draggingResizer){ case 0: //top-left imageX=mouseX; imageWidth=imageRight-mouseX; imageY=mouseY; imageHeight=imageBottom-mouseY; break; case 1: //top-right imageY=mouseY; imageWidth=mouseX-imageX; imageHeight=imageBottom-mouseY; break; case 2: //bottom-right imageWidth=mouseX-imageX; imageHeight=mouseY-imageY; break; case 3: //bottom-left imageX=mouseX; imageWidth=imageRight-mouseX; imageHeight=mouseY-imageY; break; } if(imageWidth<25) imageWidth=25; if(imageHeight<25) imageHeight=25; imageRight=imageX+imageWidth; imageBottom=imageY+imageHeight; draw(true,true); }else if(draggingImage){ imageClick=false; var dx=mouseX-startX; var dy=mouseY-startY; imageX+=dx; imageY+=dy; imageRight+=dx; imageBottom+=dy; startX=mouseX; startY=mouseY; draw(false,true); }else if(doRotation){ var dx=mouseX-imageX; var dy=mouseY-imageY; r=Math.atan2(dy,dx); draw(false,true); } } $("#canvas").mousedown(function(e){handleMouseDown(e);}); $("#canvas").mousemove(function(e){handleMouseMove(e);}); $("#canvas").mouseup(function(e){handleMouseUp(e);}); $("#canvas").mouseout(function(e){handleMouseOut(e);}); }); </script> </head> <body> <canvas id="canvas" width=800 height=500></canvas> </body> </html>

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  • C ] How can I handle weird errors from calculating acos / sin / atan2?

    - by Phrixus
    Has anyone seen this weird value while handling sin / cos/ tan / acos.. math stuff? ===THE WEIRD VALUE=== -1.#IND00 ===================== void inverse_pos(double x, double y, double& theta_one, double& theta_two) { // Assume that L1 = 350 and L2 = 250 double B = sqrt(x*x + y*y); double angle_beta = atan2(y, x); double angle_alpha = acos((L2*L2 - B*B - L1*L1) / (-2*B*L1)); theta_one = angle_beta + angle_alpha; theta_two = atan2((y-L1*sin(theta_one)), (x-L1*cos(theta_one))); } This is the code I was working on. In a particular condition - like when x & y are 10 & 10, this code stores -1.#IND00 into theta_one & theta_two. It doesn't look like either characters or numbers :( Without a doubt, atan2 / acos / stuff are the problems. But the problem is, try and catch doesn't work either cuz those double variables have successfully stored some values in them. Moreover, the following calculations never complain about it and never break the program! I'm thinking of forcing to use this value somehow and make the entire program crash... So that I can catch this error.. Except for that idea, I have no idea how I should check whether these theta_one and theta_two variables have stored this crazy values. Any good ideas? Thank you in advance..

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  • Beginner problem / error with ansi-c and gcc under ubuntu.

    - by Framester
    Hi, I am just starting programming ansi c with gcc under ubuntu (9.04). I get following error messages: error messages: main.c:6: error: expected identifier or ‘(’ before ‘/’ token In file included from /usr/include/stdio.h:75, from main.c:9: /usr/include/libio.h:332: error: expected specifier-qualifier-list before ‘size_t’ /usr/include/libio.h:364: error: expected declaration specifiers or ‘...’ before ‘size_t’ /usr/include/libio.h:373: error: expected declaration specifiers or ‘...’ before ‘size_t’ /usr/include/libio.h:493: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘_IO_sgetn’ In file included from main.c:9: /usr/include/stdio.h:314: error: expected declaration specifiers or ‘...’ before ‘size_t’ /usr/include/stdio.h:682: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘fread’ /usr/include/stdio.h:688: error: expected ‘=’, ‘,’, ‘;’, ‘asm’ or ‘__attribute__’ before ‘fwrite’ main.c:12: error: expected identifier or ‘(’ before ‘/’ token I assume it is a very simple problem, maybe in the configuration of ubuntu or gcc. I am new to programming under linux as well. I googled for help and went through a tutorial but could not find an answer. Thank you! code: #include <stdio.h> #include <math.h> int main() { printf("TestOutput\n"); return (0); } command: ~/Documents/projects/Trials$ gcc -Wall -ansi main.c

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  • algorithim for simple colision detection in Java

    - by Bob Twinkles
    I'm not very experienced with Java, just started a couple weeks ago, but I have a simple applet that has two user controlled balls, drawn through java.awt and I need a way to detect a collision with between them. I have an algorithm for detecting collision with the walls: while (true){ if (xPositon > (300 - radius)){ xSpeed = -xSpeed; } else if (xPositon < radius){ xSpeed = -xSpeed; } else if (yPositon > (300 - radius)) { ySpeed = -ySpeed; } else if (yPositon < radius){ ySpeed = -ySpeed; } xPositon += xSpeed; yPositon += ySpeed; and for the second ball if (xPositon2 > (300 - radius)){ xSpeed2 = -xSpeed2; } else if (xPositon2 < radius){ xSpeed2 = -xSpeed2; } else if (yPositon2 > (300 - radius)) { ySpeed2 = -ySpeed2; } else if (yPositon2 < radius){ ySpeed2 = -ySpeed2; } xPositon2 += xSpeed2; yPositon2 += ySpeed2; the applet is 300 pixels by 300 pixels radius stores the radius of the circles xPositon and xPositon2 store the x cordanents for the two balls yPositon and yPositon store the y cordanents for the two balls xSpeed and xSpeed2 store the x velocities for the two balls ySpeed and ySpeed2 store the y velocities for the two balls I've only taken algebra 1 so please no advanced math or physics.

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  • Project Euler, Problem 10 java solution not working

    - by Dennis S
    Hi, I'm trying to find the sum of the prime numbers < 2'000'000. This is my solution in java but I can't seem get the correct answer. Please give some input on what could be wrong and general advice on the code is appreciated. Printing 'sum' gives: 1308111344, which is incorrect. /* The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17. Find the sum of all the primes below two million. */ class Helper{ public void run(){ Integer sum = 0; for(int i = 2; i < 2000000; i++){ if(isPrime(i)) sum += i; } System.out.println(sum); } private boolean isPrime(int nr){ if(nr == 2) return true; else if(nr == 1) return false; if(nr % 2 == 0) return false; for(int i = 3; i < Math.sqrt(nr); i += 2){ if(nr % i == 0) return false; } return true; } } class Problem{ public static void main(String[] args){ Helper p = new Helper(); p.run(); } }

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  • Problems sorting by date

    - by Nathan
    I'm attempting to only display data added to my database 24 hours ago or less. However, for some reason, the code I've written isn't working, and both entries in my database, one from 1 hour ago, one from 2 days ago, show up. Is there something wrong with my equation? Thanks! public void UpdateValues() { double TotalCost = 0; double TotalEarned = 0; double TotalProfit = 0; double TotalHST = 0; for (int i = 0; i <= Program.TransactionList.Count - 1; i++) { DateTime Today = DateTime.Now; DateTime Jan2013 = DateTime.Parse("01-01-2013"); //Hours since Jan12013 int TodayHoursSince2013 = Convert.ToInt32(Math.Round(Today.Subtract(Jan2013).TotalHours)); //7 int ItemHoursSince2013 = Program.TransactionList[i].HoursSince2013; //Equals 7176, and 7130 if (ItemHoursSince2013 - TodayHoursSince2013 <= 24) { TotalCost += Program.TransactionList[i].TotalCost; TotalEarned += Program.TransactionList[i].TotalEarned; TotalProfit += Program.TransactionList[i].TotalEarned - Program.TransactionList[i].TotalCost; TotalHST += Program.TransactionList[i].TotalHST; } } label6.Text = "$" + String.Format("{0:0.00}", TotalCost); label7.Text = "$" + String.Format("{0:0.00}", TotalEarned); label8.Text = "$" + String.Format("{0:0.00}", TotalProfit); label10.Text = "$" + String.Format("{0:0.00}", TotalHST); }

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  • How to bind to another event after ajax call in jquery

    - by robert
    Hi, I'm creating a graph using flot javascript library. I have enabled clickable event and the div is binded to plotclick event. So, when a datapoint is clicked, an ajax call is made and the result is used to replace the current div. After this i need to bind the div to a new event. I tried to call bind, but it is still bound to old callback. When i call unbind and bind, the new callback is not called. var handleTeacherClick = function( event, pos, item ) { if( typeof item != "undefined" && item ) { var user_id = jQuery( 'input[name="id' + item.datapoint[0] + '"]' ).val(); jQuery.ajax({ type: 'POST', url: BASEPATH + 'index.php/ajax/home/latest', data: { "user_id": user_id }, dataType: 'json', success: function ( result ) { jQuery.plot(jQuery('#stats_prog'), result.progress_data, result.progress_options); jQuery.plot(jQuery('#stats_perf'), result.performance_data, result.performance_options); jQuery('.stats_title'). html('<span class="stats_title">'+ ' >> Chapter '+Math.ceil(item.datapoint[0])+'</span>'); jQuery('#stats_prog')./*unbind("plotclick").*/ bind('plotclick', statClickHandler ); jQuery('#stats_perf')./*unbind("plotclick"). */ bind( 'plotclick', statClickHandler ); }, }); } }

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  • calculate camera up vector after glulookat()?

    - by carrots
    I'm just starting out teaching myself openGL and now adding openAL to the mix. I have some planets scattered around in 3D space and when I touch the screen, I'm assigning a sound to a random planet and then slowly and smoothly flying the "camera" over to look at it and listen to it. The animation/tweening part is working perfectly, but the openAL piece isn't quiet right. I move the camera around by doing a tiny translate() and gluLookAt() for every frame to keep things smooth (tweening the camera position and lookAt coords). The trouble seems to be with the stereo image I'm getting out of the headphones.. it seems like the left/right/up/down is mixed up sometimes after the camera rolls or spins. I am pretty sure the trouble is here: ALfloat listenerPos[]={camera->currentX,camera->currentY,camera->currentZ}; ALfloat listenerOri[]={camera->currentLookX, camera->currentLookY, camera->currentLookZ, 0.0,//Camera Up X <--- here 0.1,//Camera Up Y <--- here 0.0}//Camera Up Z <--- and here alListenerfv(AL_POSITION,listenerPos); alListenerfv(AL_ORIENTATION,listenerOri); I'm thinking I need to recompute the UP vector for the camera after each gluLookAt() to straighten out the audio positioning problem.. but after hours of googling and experimenting I'm stuck in math that suddenly got way over my head. 1) Am I right that I need to recalculate the up vector after each gluLookAt() i do? 2) If so, can someone please walk me though figuring out how to do that?

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  • Accessing a Class Member from a First-Class Function

    - by dbyrne
    I have a case class which takes a list of functions: case class A(q:Double, r:Double, s:Double, l:List[(Double)=>Double]) I have over 20 functions defined. Some of these functions have their own parameters, and some of them also use the q, r, and s values from the case class. Two examples are: def f1(w:Double) = (d:Double) => math.sin(d) * w def f2(w:Double, q:Double) = (d:Double) => d * q * w The problem is that I then need to reference q, r, and s twice when instantiating the case class: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0, 0.5))) //0.5 is referenced twice I would like to be able to instantiate the class like this: A(0.5, 1.0, 2.0, List(f1(3.0), f2(4.0))) //f2 already knows about q! What is the best technique to accomplish this? Can I define my functions in a trait that the case class extends? EDIT: The real world application has 7 members, not 3. Only a small number of the functions need access to the members. Most of the functions don't care about them.

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  • incremental way of counting quantiles for large set of data

    - by Gacek
    I need to count the quantiles for a large set of data. Let's assume we can get the data only through some portions (i.e. one row of a large matrix). To count the Q3 quantile one need to get all the portions of the data and store it somewhere, then sort it and count the quantile: List<double> allData = new List<double>(); foreach(var row in matrix) // this is only example. In fact the portions of data are not rows of some matrix { allData.AddRange(row); } allData.Sort(); double p = 0.75*allData.Count; int idQ3 = (int)Math.Ceiling(p) - 1; double Q3 = allData[idQ3]; Now, I would like to find a way of counting this without storing the data in some separate variable. The best solution would be to count some parameters od mid-results for first row and then adjust it step by step for next rows. Note: These datasets are really big (ca 5000 elements in each row) The Q3 can be estimated, it doesn't have to be an exact value. I call the portions of data "rows", but they can have different leghts! Usually it varies not so much (+/- few hundred samples) but it varies! This question is similar to this one: http://stackoverflow.com/questions/1058813/on-line-iterator-algorithms-for-estimating-statistical-median-mode-skewness But I need to count quantiles. ALso there are few articles in this topic, i.e.: http://web.cs.wpi.edu/~hofri/medsel.pdf http://portal.acm.org/citation.cfm?id=347195&dl But before I would try to implement these, I wanted to ask you if there are maybe any other, qucker ways of counting the 0.25/0.75 quantiles?

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  • How Would a Newborn Baby Learn Web Programming?

    - by Mugatu
    Hello all, I chose that title because I equate my knowledge of web programming and web development with that of a newborn. Here's the shortest version of my story and what I'm looking to do: A friend and I have been coming up with website ideas for a couple years, mostly just jotting them down whenever we come up with a good, useful idea when browsing the web. For the past 6 months we've hired a couple different programmers to make a couple of the sites for us, but have been disappointed with how it's gone. Been too slow and too many miscommunications for our liking. So like the saying goes if you want something done right do it yourself, we're going to do it ourselves. I know nothing about programming, I've never written a line of code in my life. I consider myself very good with math and about as logical as you can get, but I have zero real-life programming knowledge. The sites we want to make are all pretty 'Web 2.0'ish', meaning user-generated content, commenting on posts, pages that change on the fly, etc. So here are some of my questions for anyone who's been there before: Is there a language you'd recommend learning first? Something that is a good indicator how most other languages work? What web programming languages do you recommend learning first based on popularity both now and the future. I don't want to learn a language that's going to be outdated by the time I'm an expert at it. Any specific books you'd recommend? Any general advice you'd give to someone literally starting at square zero for coding who plans on being in it for the long haul? Thanks in advance for the help

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  • gluLookAt vectors and FPS-style camera

    - by Kevin Pamplona
    I am attempting to implemented an FPS-style camera by updating three vectors: EYE, DIR, UP. These vectors are the same that are used by gluLookAt (since gluLookAt is specified by the position of the camera, the direction it is looking at, and an up vector). I have already implemented the left-right and up-down strafing movements, but I'm having a lot of trouble understanding the math behind making the camera look-around while remaining stationary. In this case, the EYE vector remains the same, while I must update DIR and UP. Below is the code I tried, but it doesn't seem to work properly. Any suggestions? Thanks. void Transform::left(float degrees, vec3& dir, vec3& up) { vec3 axis; axis = glm::normalize(up); mat3 R = rotate(-degrees, axis); dir = R*dir; dir = R*up; }; void Transform::up(float degrees, vec3& dir, vec3& up) { vec3 axis; axis=glm::normalize(glm::cross(dir,up)); mat3 R = rotate(-degrees, axis); dir = R*dir-; up = R*up; };

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  • Problem with jQuery slider - time

    - by Dawid
    Hello. I'd like to make a slider to choose time(from 1:00 to 4:00) but it doesn't work. It doesn't communicate with 'select'. Can anyone help me? <script> $(function() { var select = $( "#czastrwania" ); var slider = $( "<div id='slider'></div>" ).insertAfter( select ).slider({ min: 60, max: 240, step: 30, range: "min", value: select[ 0 ].selectedIndex + 1, slide: function( e, ui ) { var hours = Math.floor(ui.value / 60); var minutes = ui.value - (hours * 60); if(hours.length == 1) hours = '0' + hours; if(minutes.length == 1) minutes = '0' + minutes; select[ 0 ].selectedIndex = ui.value - 1; } }); $( "#czastrwania" ).change(function() { slider.slider( "value", this.selectedIndex + 1 ); }); }); </script> <select id="czastrwania" name="czastrwania"> <option value="1:00">1:00</option> <option value="1:30">1:30</option> <option value="2:00">2:00</option> <option value="2:30">2:30</option> <option value="3:00">3:00</option> <option value="3:30">3:30</option> <option value="4:00">4:00</option> </select>

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  • How can someone with no experience learn how to program?

    - by Mugatu
    A friend and I have been coming up with website ideas for a couple years, mostly just jotting them down whenever we come up with a good, useful idea when browsing the web. For the past 6 months we've hired a couple different programmers to make a couple of the sites for us, but have been disappointed with how it's gone. Been too slow and too many miscommunications for our liking. So like the saying goes if you want something done right do it yourself, we're going to do it ourselves. I know nothing about programming, I've never written a line of code in my life. I consider myself very good with math and about as logical as you can get, but I have zero real-life programming knowledge. The sites we want to make are all pretty 'Web 2.0'ish', meaning user-generated content, commenting on posts, pages that change on the fly, etc. So here are some of my questions for anyone who's been there before: Is there a language you'd recommend learning first? Something that is a good indicator how most other languages work? What web programming languages do you recommend learning first based on popularity both now and the future. I don't want to learn a language that's going to be outdated by the time I'm an expert at it. Any specific books you'd recommend? Any general advice you'd give to someone literally starting at square zero for coding who plans on being in it for the long haul?

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  • Reversible numerical calculations in Prolog

    - by user8472
    While reading SICP I came across logic programming chapter 4.4. Then I started looking into the Prolog programming language and tried to understand some simple assignments in Prolog. I found that Prolog seems to have troubles with numerical calculations. Here is the computation of a factorial in standard Prolog: f(0, 1). f(A, B) :- A > 0, C is A-1, f(C, D), B is A*D. The issues I find is that I need to introduce two auxiliary variables (C and D), a new syntax (is) and that the problem is non-reversible (i.e., f(5,X) works as expected, but f(X,120) does not). Naively, I expect that at the very least C is A-1, f(C, D) above may be replaced by f(A-1,D), but even that does not work. My question is: Why do I need to do this extra "stuff" in numerical calculations but not in other queries? I do understand (and SICP is quite clear about it) that in general information on "what to do" is insufficient to answer the question of "how to do it". So the declarative knowledge in (at least some) math problems is insufficient to actually solve these problems. But that begs the next question: How does this extra "stuff" in Prolog help me to restrict the formulation to just those problems where "what to do" is sufficient to answer "how to do it"?

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  • Shuffling words in a sentence in javascript (coding horror - How to improve?)

    - by Bill Zimmerman
    Hi, I'm trying to do something that is fairly simple, but my code looks terrible and I am certain there is a better way to do things in javascript. I am new to javascript, and am trying to improve my coding. This just feels very messy. All I want to do is to randomly change the order some words on a web page. In python, the code would look something like this: s = 'THis is a sentence' shuffledSentence = random.shuffle(s.split(' ')).join(' ') However, this is the monstrosity I've managed to produce in javascript //need custom sorting function because javascript doesn't have shuffle? function mySort(a,b) { return a.sortValue - b.sortValue; } function scrambleWords() { var content = $.trim($(this).contents().text()); splitContent = content.split(' '); //need to create a temporary array of objects to make sorting easier var tempArray = new Array(splitContent.length); for (var i = 0; i < splitContent.length; i++) { //create an object that can be assigned a random number for sorting var tmpObj = new Object(); tmpObj.sortValue = Math.random(); tmpObj.string = splitContent[i]; tempArray[i] = tmpObj; } tempArray.sort(mySort); //copy the strings back to the original array for (i = 0; i < splitContent.length; i++) { splitContent[i] = tempArray[i].string; } content = splitContent.join(' '); //the result $(this).text(content); } Can you help me to simplify things?

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  • PHP/WordPress Session CountDown

    - by Cameron
    I have the following code to show how long a user has left before their session will expire, I am using WordPress. How can I do this? Thanks <script> var obj_Span; var n_Seconds = 0; var n_Minutes = 0; var n_Hours = 0; function F_ConvertNumberToString ( n_Num ) { var str_Num = String(n_Num); if ( str_Num.length < 2 ) str_Num = "0" + str_Num; return str_Num; } function F_CountDown () { if ( n_Hours == 0 && n_Minutes == 0 && n_Seconds == 0 ) { obj_Span.innerHTML = "(Sorry, your session has expired.)"; } else { if ( n_Seconds >= 0 ) n_Seconds --; if ( n_Seconds < 0 ) { n_Minutes --; n_Seconds = 59; } if ( n_Minutes >= 0 ) { window.setTimeout ( "F_CountDown()", 1000 ); } if ( n_Minutes < 0 ) { n_Hours --; n_Minutes = 59; window.setTimeout ( "F_CountDown()", 1000 ); } F_UpdateDisplay (); } } function F_UpdateDisplay ( ) { if ( document.getElementById ) { if (n_Hours > 0 ) obj_Span.innerHTML = "(Remaining " + F_ConvertNumberToString(n_Hours) + ":" + F_ConvertNumberToString(n_Minutes) + ":" + F_ConvertNumberToString(n_Seconds) + ")"; else obj_Span.innerHTML = "(Remaining " + F_ConvertNumberToString(n_Minutes) + ":" + F_ConvertNumberToString(n_Seconds) + ")"; } } function F_StartCountDown ( n_Session ) { obj_Span = document.getElementById ( "CountDown" ); n_Minutes = n_Session; n_Hours = Math.floor(n_Minutes/60); n_Minutes = n_Minutes - (60*n_Hours); F_CountDown (); } </script> <script> F_StartCountDown ( " code here... " ); </script> <span id="CountDown"></span>

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  • DOMAIN REDIRECT PROBLEM WITH JQUERY / JAVASCRIPT

    - by GiovanniDema
    Hi guys, first time here. I got a strange problem. I have a fullscreen image scaler javascript (as GOTOCHINA website) that works very well on my website. Then, I purchased a domain redirect pointing on my website and when redirecting suddenly internet explorer 7 and internet explorer 8 give me this error Messagge: is not a valid argument. Line: 34 Char: 17 URI: http://*****/scaler.js The script is var db=document.body; var imag=document.getElementById('wallpaper'); var dbsize={}; var imgsrc=imag.src; var keyStop=function(e){ var e=window.event||e||{}; var tag=e.target.tagName.toLowerCase(); if(tag!='textarea'&&!(tag=='input'&&(e.target.type=='text'||e.target.type=='password'))){ if(e.keyCode==32||e.keyCode==39||e.keyCode==40){ if(e.preventDefault)e.preventDefault(); else e.returnValue=false; } } } if(this.addEventListener)window.addEventListener('keydown',keyStop,false); else window.attachEvent('onkeydown',keyStop); setInterval(function(){ window.scrollTo(0,0); if(imag.complete){ if(db.clientWidth!=dbsize.w||db.clientHeight!=dbsize.h||imag.src!=imgsrc){ imgsrc=imag.src; var dbsizew=db.clientWidth; var dbsizeh=db.clientHeight; var newwidth=Math.round(dbsizeh*(imag.offsetWidth/imag.offsetHeight)); var nextvar=dbsizewnewwidth?dbsizew:newwidth; imag.style.width=nextvar+'px'; } } },300); In other words when i open the official website everything's working correctly. When i open redirect domain pointing on official website... the previous error appears. The line is exactly this - imag.style.width=nextvar+'px'; Thanks in advance Giovanni

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  • Numerical calculations in Prolog

    - by user8472
    While reading SICP I came across logic programming chapter 4.4. Then I started looking into the Prolog programming language and tried to understand some simple assignments in Prolog. I found that Prolog seems to have troubles with numerical calculations. Here is the computation of a factorial in standard Prolog: f(0, 1). f(A, B) :- A > 0, C is A-1, f(C, D), B is A*D. The issues I find is that I need to introduce two auxiliary variables (C and D), a new syntax (is) and that the problem is non-reversible (i.e., f(5,X) works as expected, but f(X,120) does not). Naively, I expect that at the very least C is A-1, f(C, D) above may be replaced by f(A-1,D), but even that does not work. My question is: Why do I need to do this extra "stuff" in numerical calculations but not in other queries? I do understand (and SICP is quite clear about it) that in general information on "what to do" is insufficient to answer the question of "how to do it". So the declarative knowledge in (at least some) math problems is insufficient to actually solve these problems. But that begs the next question: How does this extra "stuff" in Prolog help me to restrict the formulation to just those problems where "what to do" is sufficient to answer "how to do it"?

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  • Do variable references (alias) incure runtime costs in c++?

    - by cheshirekow
    Maybe this is a compiler specific thing. If so, how about for gcc (g++)? If you use a variable reference/alias like this: int x = 5; int& y = x; y += 10; Does it actually require more cycles than if we didn't use the reference. int x = 5; x += 10; In other words, does the machine code change, or does the "alias" happen only at the compiler level? This may seem like a dumb question, but I am curious. Especially in the case where maybe it would be convenient to temporarily rename some member variables just so that the math code is a little easier to read. Sure, we're not exactly talking about a bottleneck here... but it's something that I'm doing and so I'm just wondering if there is any 'actual' difference... or if it's only cosmetic.

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  • Java Concurrency in practice sample question

    - by andy boot
    I am reading "Java Concurrency in practice" and looking at the example code on page 51. This states that if a thread has references to a shared object then other threads may be able to access that object before the constructor has finished executing. I have tried to put this into practice and so I wrote this code thinking that if I ran it enough times a RuntimeException("World is f*cked") would occur. But it isn't doing. Is this a case of the Java spec not guaranting something but my particular implementation of java guaranteeing it for me? (java version: 1.5.0 on Ubuntu) Or have I misread something in the book? Code: (I expect an exception but it is never thrown) public class Threads { private Widgit w; public static void main(String[] s) throws Exception { while(true){ Threads t = new Threads(); t.runThreads(); } } private void runThreads() throws Exception{ new Checker().start(); w = new Widgit((int)(Math.random() * 100) + 1); } private class Checker extends Thread{ private static final int LOOP_TIMES = 1000; public void run() { int count = 0; for(int i = 0; i < LOOP_TIMES; i++){ try { w.checkMe(); count++; } catch(NullPointerException npe){ //ignore } } System.out.println("checked: "+count+" times out of "+LOOP_TIMES); } } private static class Widgit{ private int n; private int n2; Widgit(int n) throws InterruptedException{ this.n = n; Thread.sleep(2); this.n2 = n; } void checkMe(){ if (n != n2) { throw new RuntimeException("World is f*cked"); } } } }

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  • why is a minus sign prepended to my biginteger?

    - by kyrogue
    package ewa; import java.io.UnsupportedEncodingException; import java.security.MessageDigest; import java.security.NoSuchAlgorithmException; import java.util.logging.Level; import java.util.logging.Logger; import java.math.BigInteger; /** * * @author Lotus */ public class md5Hash { public static void main(String[] args) throws NoSuchAlgorithmException { String test = "abc"; MessageDigest md = MessageDigest.getInstance("MD5"); try { md.update(test.getBytes("UTF-8")); byte[] result = md.digest(); BigInteger bi = new BigInteger(result); String hex = bi.toString(16); System.out.println("Pringting result"); System.out.println(hex); } catch (UnsupportedEncodingException ex) { Logger.getLogger(md5Hash.class.getName()).log(Level.SEVERE, null, ex); } } } i am testing conversion of byte to hex and when done, the end result has a minus sign on the beginning of the string, why does this happen? i have read the docs and it says it will add a minus sign, however i do not understand it. And will the minus sign affect the hash result? because i am going to implement it to hash password stored on my database

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  • SetInterval missing property in js class

    - by sebastian
    I wrote simple class in JS witch works, but i had problem when i try use setInterval with it. Ex. if i do something like that ball = new ball(5,10,0, '#canvas'); ball.draw(); ball.draw(); ball.draw(); ball.draw(); It works. But this: ball = new ball(5,10,0, '#canvas'); setInterval(ball.draw, 100); Not work. I get error that values are undefined. function ball (x,y,z,holdingEl) { this.r = 5; //zmienna przechowujaca promien pilki this.size = this.r *2; // zmienna przechowujaca rozmiar this.ballSpeed = 100; // predkosc pilki this.ballWeight = 0.45; // masa pilki this.maxFootContactTime = 0.2; // maksymalny czas kontaktu pilki z noga - stala this.ctx = jQuery(holdingEl)[0].getContext("2d"); // obiekt pilki this.intVal = 100 // predkosc odswiezania this.currentPos = { // wspolrzedne pozycji x: x, y: y, z: z } this.interactionPos = { // wspolrzedne pozycji ostatniej interakcji x: -1, y: -1, z: -1 } this.direct = { // kierunek w kazdej plaszczyznie x : 1, y : 0, z : 0 } this.draw = function (){ this.ctx.clearRect(0,0,1100,800); this.ctx.beginPath(); this.ctx.arc(this.currentPos.x, this.currentPos.y, this.r, 0, Math.PI*2, true); this.ctx.closePath(); this.ctx.fill(); } }

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  • Which fieldtype is best for storing PRICE values?

    - by BerggreenDK
    Hi there I am wondering whats the best "price field" in MSSQL for a shoplike structure? Looking at this overview: http://www.teratrax.com/sql_guide/data_types/sql_server_data_types.html We have datatypes called money, smallmoney, then we have decimal/numeric and lastly float and real Name, memory/disk-usage and value ranges: Money: 8 bytes (values: -922,337,203,685,477.5808 to +922,337,203,685,477.5807) Smallmoney: 4 bytes (values: -214,748.3648 to +214,748.3647) Decimal: 9 [default, min. 5] bytes (values: -10^38 +1 to 10^38 -1 ) Float: 8 bytes (values: -1.79E+308 to 1.79E+308 ) Real: 4 bytes (values: -3.40E+38 to 3.40E+38 ) My question is: is it really wise to store pricevalues in those types? what about eg. INT? Int: 4 bytes (values: -2,147,483,648 to 2,147,483,647) Lets say a shop uses dollars, they have cents, but I dont see prices being $49.2142342 so the use of a lot of decimals showing cents seems waste of SQL bandwidth. Secondly, most shops wouldn't show any prices near 200.000.000 (not in normal webshops at least... unless someone is trying to sell me a famous tower in Paris) So why not go for an int? An int is fast, its only 4 bytes and you can easily make decimals, by saving values in cents instead of dollars and then divide when you present the values. The other approach would be to use smallmoney which is 4 bytes too, but this will require the math part of the CPU to do the calc, where as Int is integer power... on the downside you will need to divide every single outcome. Are there any "currency" related problems with regionalsettings when using smallmoney/money fields? what will these transfer too in C#/.NET ? Any pros/cons? Go for integer prices or smallmoney or some other? Whats does your experience tell?

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