Tutorial by Examples: id

Assume you want to delegate to a class but you do not want to provide the delegated-to class in the constructor parameter. Instead, you want to construct it privately, making the constructor caller unaware of it. At first this might seem impossible because class delegation allows to delegate only to...

// circle objects: { x:, y:, radius: } // return true if the 2 circles are colliding // c1 and c2 are circles as defined above function CirclesColliding(c1,c2){ var dx=c2.x-c1.x; var dy=c2.y-c1.y; var rSum=c1.radius+c2.radius; return(dx*dx+dy*dy<=rSum*rSum); }

// rectangle objects { x:, y:, width:, height: } // return true if the 2 rectangles are colliding // r1 and r2 are rectangles as defined above function RectsColliding(r1,r2){ return !( r1.x>r2.x+r2.width || r1.x+r1.width<r2.x || r1.y>r2.y+r2.height || ...

// rectangle object: { x:, y:, width:, height: } // circle object: { x:, y:, radius: } // return true if the rectangle and circle are colliding function RectCircleColliding(rect,circle){ var dx=Math.abs(circle.x-(rect.x+rect.width/2)); var dy=Math.abs(circle.y-(rect.y+rect.height/2));...

// [x0,y0] to [x1,y1] define a line segment // [cx,cy] is circle centerpoint, cr is circle radius function isCircleSegmentColliding(x0,y0,x1,y1,cx,cy,cr){ // calc delta distance: source point to line start var dx=cx-x0; var dy=cy-y0; // calc delta distance: line start to e...

// var rect={x:,y:,width:,height:}; // var line={x1:,y1:,x2:,y2:}; // Get interseting point of line segment & rectangle (if any) function lineRectCollide(line,rect){ // p=line startpoint, p2=line endpoint var p={x:line.x1,y:line.y1}; var p2={x:line.x2,y:line.y2}; // to...

Use the Separating Axis Theorem to determine if 2 convex polygons are intersecting THE POLYGONS MUST BE CONVEX Attribution: Markus Jarderot @ How to check intersection between 2 rotated rectangles? // polygon objects are an array of vertices forming the polygon // var polygon1=[{x:100,y:100}...

Tests all polygon sides for intersections to determine if 2 polygons are colliding. // polygon objects are an array of vertices forming the polygon // var polygon1=[{x:100,y:100},{x:150,y:150},{x:50,y:150},...]; // The polygons can be both concave and convex // return true if the 2 polygons ...

Tests if the [x,y] point is inside a closed arc. var arc={ cx:150, cy:150, innerRadius:75, outerRadius:100, startAngle:0, endAngle:Math.PI } function isPointInArc(x,y,arc){ var dx=x-arc.cx; var dy=y-arc.cy; var dxy=dx*dx+dy*dy; var rrOuter=arc.outerRadiu...

Tests if the [x,y] point is inside a wedge. // wedge objects: {cx:,cy:,radius:,startAngle:,endAngle:} // var wedge={ // cx:150, cy:150, // centerpoint // radius:100, // startAngle:0, endAngle:Math.PI // } // Return true if the x,y point is inside the closed wedge function is...

Tests if an [x,y] point is inside a circle. // circle objects: {cx:,cy:,radius:,startAngle:,endAngle:} // var circle={ // cx:150, cy:150, // centerpoint // radius:100, // } // Return true if the x,y point is inside the circle function isPointInCircle(x,y,circle){ var dx=x-circ...

Tests if an [x,y] point is inside a rectangle. // rectangle objects: {x:, y:, width:, height: } // var rect={x:10, y:15, width:25, height:20} // Return true if the x,y point is inside the rectangle function isPointInRectangle(x,y,rect){ return(x>rect.x && x<rect.x+rect.width...

Here the steps required to create a Firebase project and to connect it with an Android app. Add Firebase to your app Create a Firebase project in the Firebase console and click Create New Project. Click Add Firebase to your Android app and follow the setup steps. When prompted, enter...

The qsort() standard library function is a good example of how one can use void pointers to make a single function operate on a large variety of different types. void qsort ( void *base, /* Array to be sorted */ size_t num, /...

Implementation on Android is a bit more work and requires a specific Service to be implemented. First lets check if our device is capable of receiving push notifications, and if so, register it with Google. This can be done with this code in our MainActivity.cs file. protected override void OnCrea...

Ruby keeps track of local variables and self variable via an object called binding. We can get binding of a scope with calling Kernel#binding and evaluate string inside a binding via Binding#eval. b = proc do local_variable = :local binding end.call b.eval "local_variable" #=&gt...

C99 Since C99, C has variable length arrays, VLA, that model arrays with bounds that are only known at initialization time. While you have to be careful not to allocate too large VLA (they might smash your stack), using pointers to VLA and using them in sizeof expressions is fine. double sumAll(si...

Introduction Play has several plugins for different IDE-s. The eclipse plugin allows to transform a Play application into a working eclipse project with the command activator eclipse. Eclipse plugin may be set per project or globally per sbt user. It depends on team work, which approach should be u...

Since Yii2 version 2.0.4 there is the EachValidator used to validate each item in an array. [ // ... other rules ['userIDs', 'each', 'rule' => ['integer']], ] The ['integer'] part can be every other validator object that Yii2 offers and can hold the specific arguments for the valid...

void methods can be stubbed using the doThrow(), doAnswer(), doNothing(), doCallRealMethod() family of methods. Runnable mock = mock(Runnable.class); doThrow(new UnsupportedOperationException()).when(mock).run(); mock.run(); // throws the UnsupportedOperationException Note thatvoid methods...