bit | 易学教程

How can I set bit column to null?

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问题 The following only wants a primitive boolean (true or false). psmt.setBoolean(5, boolean) ; //wants primitive What if I want to set the bit to null? Sql server = [bit] NULL 回答1: You could use setNull preparedStatement.setNull(5, Types.BOOLEAN); 来源： https://stackoverflow.com/questions/26184937/how-can-i-set-bit-column-to-null

Write bit value to database

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问题 I'm trying to write a bit value (true or false) into my database in a field called "processed". i'm currently trying to do this by passing in bool values, but I get an error saying can't convert from type varchar to bit. Can anybody see what is going on in my logic? protected void CheckBoxProcess_CheckedChanged(object sender, EventArgs e) { bool update; bool trueBool = true; bool falseBool = false; string checkedString = "UPDATE SecureOrders SET processed = '%" + trueBool + "%' WHERE fName

Write bit value to database

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How to convert a Seq[Byte] into an Array[Boolean] representing each bit in Scala

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问题 Is there a better way to convert a sequence of Bytes into an Seq[Boolean] where each element represents a bit from the Byte sequence? I'm currently doing this, but byte2Bools seems a little too heavy... object Main extends App { private def byte2Bools(b: Byte) = (0 to 7).foldLeft(ArrayBuffer[Boolean]())((bs, i) => bs += isBitSet(b, i)) private def isBitSet(byte: Byte, bit: Int) = ((byte >> bit) & 1) == 1 val bytes = List[Byte](1, 2, 3) val bools = bytes.flatMap(b => byte2Bools(b)) println

并发与并行(concurrency vs parallesim)

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最近对计算机中并发（concurrency）和并行（parallesim）这两个词的区别很迷惑，将搜索到的相关内容整理如下。 http://www.vaikan.com/docs/Concurrency-is-not-Parallelism/#slide-7 定义：并发 Concurrency 将相互独立的执行过程综合到一起的编程技术。并行 Parallelism 同时执行(通常是相关的)计算任务的编程技术。并发 vs. 并行并发是指同时处理很多事情。而并行是指同时能完成很多事情。两者不同，但相关。一个重点是组合，一个重点是执行。并发提供了一种方式让我们能够设计一种方案将问题(非必须的)并行的解决。并发是一种将一个程序分解成小片段独立执行的程序设计方法。通信是指各个独立的执行任务间的合作。这是Go语言采用的模式，包括Erlang等其它语言都是基于这种SCP模式： C. A. R. Hoare: Communicating Sequential Processes (CACM 1978) 第二种： https://laike9m.com/blog/huan-zai-yi-huo-bing-fa-he-bing-xing,61/ “并发”指的是程序的结构，“并行”指的是程序运行时的状态即使不看详细解释，也请记住这句话。下面来具体说说：并行（parallesim

杰理AC692X---LED点灯

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根据原厂SDK进行讲解首先打开LED宏定义（sdk_cfg.h）：选择点灯方式(led.h)：一般选择PA/B/C/D口，PR口是在低功耗（假关机）模式下选择。LED驱动方式一般选择普通。 # define LED_PORTX JL_PORTA # define LED_BLUE BIT(3) # define LED_RED BIT(2) 根据项目需求配置GPIO口。上面代码配置的是PA3&PA2口。 # define LED_INIT_EN() do{LED_PORTX->PU &= ~LED_BLUE;LED_PORTX->PD &= ~LED_BLUE;LED_PORTX->DIR &= ~LED_BLUE;\ LED_PORTX->PU &= ~LED_RED;LED_PORTX->PD &= ~LED_RED;LED_PORTX->DIR &= ~LED_RED;}while(0) # define LED_INIT_DIS() do{LED_PORTX->PU &= ~LED_BLUE;LED_PORTX->PD &= ~LED_BLUE;LED_PORTX->DIR |= LED_BLUE;\ LED_PORTX->PU &= ~LED_RED;LED_PORTX->PD &= ~LED_RED;LED_PORTX->DIR |= LED_RED;}while

What is the easiest way to set custom binary data messages in Java?

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问题 Coming from the world of C# and brushing up on Java, I have learned that there are no unsigned bytes/ints. I am trying to find out what is the easiest way build up custom binary messages such as the following example: As you can see, certain integer values need to put into a 3 bit slot. others values are single bit flags, or other size fields. From what I have read, I should work in the "next larger" primitive, such as building binary bytes in integers using bit wise operators. Are there

C# NOT (~) bit wise operator returns negative values

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问题 Why does C#'s bitwise NOT operator return (the_number*-1)-1 ? byte a = 1; Console.WriteLine(~a); //equals -2 byte b = 9; Console.WriteLine(~b); //equals -10 // Shouldn't a=0 and b=6? How would I do this in C#? 9 = 0b1001 -> NOT = 0b0110 = 6 回答1: Bitwise operations return a value of type int (signed). Signed integers use two's-complement to represent negative numbers. Sign extension is used when going from byte to int. byte a = 1; // 0b00000001 int notA = ~a; // 0b11111110 = -128 + 64 + 32 +

How do bit fields and their alignments work in C programming?

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问题 I need your help at understanding how bit fields work in C programming. I have declared this struct: struct message { unsigned char first_char : 6; unsigned char second_char : 6; unsigned char third_char : 6; unsigned char fourth_char : 6; unsigned char fifth_char : 6; unsigned char sixth_char : 6; unsigned char seventh_char : 6; unsigned char eigth_char : 6; }__packed message; I saved the size of the struct into an integer using sizeof(message). I thought the value of the size will be 6

C# Rotate bits to left overflow issue

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问题 I've been trying to get this to work for several days now, i've read a thousand guides and people's questions, but still, i cant find a way to do it properly. What i want to do is to rotate the bits to the left, here's an example. Original number = 10000001 = 129 What i need = 00000011 = 3 I have to rotate the bits to left a certain ammount of times (it depends on what the user types), here's what i did: byte b = (byte)129; byte result = (byte)((byte)b << 1); Console.WriteLine(result);