overflow | 易学教程

Is this an overflow arithmetic calculation?

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问题 So when I read the book and it says that overflow can't occur when add different signs and subtraction of the same sign. But I have question when I do this: 185 - 122 I converted binary of 122 to 2s complement and did the addition, which is different signs: 185+(-122) and when I add them together, I got the sign bit overflow to 100111111. But if I cut off the MSB on the left, it is the correct answer. Is it an overflow? 回答1: No, it isn't overflow - the overflow resulting from the addition of

Handling Huge Multidimensional Arrays in C++

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问题 I'm designing a game in C++ similar to Minecraft that holds an enormous amount of terrain data in memory. In general, I want to store an array in memory that is [5][4][5][50][50][50]. This isn't bad since it amounts to about 100mb of virtual memory since my structure will only be about 8 bytes. However, I'm having trouble figuring out the best way to handle this. I do want this to be in virtual memory, but obviously not on the stack. And I keep making the mistake some how of creating this

Remove scollbar when no need to scroll

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问题 I have a div with a scollbar as a result of the CSS below. However, when there is no need to scroll, the bar is still there. There is no slider/arrows, but an emtpy bar is just there. Is there a way to only show the bar if the content overflows? Thanks. #id{ overflow: -moz-scrollbars-vertical; overflow-x: hidden; overflow-y: scroll; } 回答1: use overflow: auto; then overflow will only be displayed if it actually overflows auto The behavior of auto isn’t specified in any detail in the CSS2.1

CSS清除浮动float方法总结

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使用浮动造成的BUG：使用浮动前：（子节点是将父节点撑开了）代码如下 1 <div class="box"> 2 <div class="d1">1</div> 3 <div class="d2">2</div> 4 </div> 5 .box{ 6 border: 1px solid black； 8 margin: 50px auto; 9 padding: 50px; 10 color: #fff; 11 } 12 .d1{ 13 float: left; 14 background: purple; 15 width: 100px; 16 height: 100px; 17 } 18 .d2{ 19 float: left; 20 background: #9c3; 21 width: 100px; 22 height: 100px; 23 } 首先说明现象：我没有给父节点设置高度，在给子div设置float:left后，出现如下BUG: 1.父节点的margin属性失效 2.子节点没有将父节点撑开那么，我们该怎么解决这样由浮动造成的bug呢？三种方法：一、 :after的3行代码（最高大上的方法,写情书的感觉哟）原理：利用:after和:before在元素内插入两个元素块（其实就是在节点本身构造出两个存在于Render Tree的节点）

Use full width excluding overflow scrollbar with “position: absolute”

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问题 I would like to have a small red div with full width at a fixed top position, inside another div that has overflow: scroll . I hope the jsFiddle makes it clear: http://jsfiddle.net/mCYLm/2/. The issue is that the red div is overlapping the scrollbar. I guess right: 0 means the right hand side of div.wrapper ; it does not subtract the scrollbar of div.main . When I move the overflow: scroll into div.wrapper , then the red banner has the right size (fiddle). However, it is not at a fixed

Use full width excluding overflow scrollbar with “position: absolute”

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Does BigInteger ever overflows?

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问题 The API docs says All of the details in the Spec concerning overflow are ignored, as BigIntegers are made as large as necessary to accommodate the results of an operation. Does this implies BigInteger will never overflow assuming you have sufficient memory available ? If so why do we let some "type" overflow and some don't ? As the language evolves, will it favor the types which hide overflowing mechanism from the programmers ? 回答1: BigInteger will never overflow assuming you have enough

Add padding without changing overall width

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问题 How can I add padding to an element without adding on top of the predefined width? It's good to define the width of a column to make a clean grid for the layout; but also wants to add padding to the contents inside the column. Any way to specify that? 回答1: element { -webkit-box-sizing: border-box; /* Safari/Chrome, other WebKit */ -moz-box-sizing: border-box; /* Firefox, other Gecko */ box-sizing: border-box; /* Opera/IE 8+ */ } 回答2: Use box-sizing, it makes padding inclusive: https:/

how to call function from other fragment class

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问题 I'm trying to call this function public void arrowClick() is inside my main fragment public class CounterMain extends Fragment implements View.OnClickListener{ the fragment is extend android.support.v4.app.Fragment I want to call this function from another Custmoe Dialog fragment public class CustmoeDialog extends DialogFragment { I tried ((CounterMain)getActivity()).arrowClick(); but I can't use it it says android.support.v4.app.Fragment cannot be cast to my.example.CounterMain and the

Floating div not displaying background color when i am not using overflow?

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问题 HTML : <div id="wrapper"> <div id="content"> <div id="slider"></div> <div id="left"></div> <div id="right"></div> </div> </div> CSS : #wrapper { background:blue; width:990px; margin:0 auto; } #content { width:990px; height:auto; } #slider { width:990px; /* slider jquery */ height:auto; } #left { float:left; width:490px; } #right { float:right; width:490px; } Live demo: Tinkerbin But in left and right div blue color is not displaying , If i am giving overflow:hidden to wrapper then its work