I want to create a char** character array on the stack. Currently, I'm using this, but I wonder if there is a nicer way: char* buf[4]; char temp0[1024], temp1[1024], temp2[1024], temp3[1024]; buf[0] = temp0; buf[1] = temp1; buf[2] = temp2; buf[3] = temp3; EDIT: To be more clear, I can not simply use char buf[4][1024] . A function expecting an array of char pointers would crash, as it'
我想在堆栈上创建char **字符数组。 目前,我正在使用它,但我想知道是否有更好的方法: char* buf[4]; char temp0[1024], temp1[1024], temp2[1024], temp3[1024]; buf[0] = temp0; buf[1] = temp1; buf[2] = temp2; buf[3] = temp3; 编辑:为了更清楚,我不能简单地使用char buf[4][1024] 。 期望一个char指针数组的函数会崩溃,因为它是一个根本不同的数据类型。 这是我将如何在堆上创建数组: char** buf = malloc(size
I have some C code that is something of a puzzle. For a reason to do with this code, I'm wondering how I can tell if a struct object is ending up on the heap or stack? The objects are not being created with malloc or calloc . They start their life in the form of an array. For the purposes of this post, I'm going to call the struct Emp. Emp myEmp[6]; /* Each myEmp[?] item is populat
我有一些C代码是一个难题。 为了解决这个问题,我想知道如何判断一个struct对象是堆栈还是堆栈? 这些对象不是用malloc或calloc创建的。 他们以阵列的形式开始他们的生活。 为了这篇文章的目的,我打算调用struct Emp。 Emp myEmp[6]; /* Each myEmp[?] item is populated in code */ 对象以各种方式排序和操作,并且在某些时候,对象被复制并交给数组指针。 拷贝通过memcpy完成。 然后将这些对象放入如下内容中: Emp
Are there machines (or compilers), where sizeof(char) != 1 ? Does C99 standard says that sizeof(char) on standard compliance implementation MUST be exactly 1? If it does, please, give me section number and citation. Update: If I have a machine (CPU), which can't address bytes (minimal read is 4 bytes, aligned), but only 4-s of bytes ( uint32_t ), can compiler for this machine define size
是否有机器(或编译器),其中sizeof(char) != 1 ? C99标准是否规定标准合规实现的sizeof(char)必须是1? 如果是这样,请给我部分号码和引文。 更新:如果我的计算机(CPU)无法寻址字节(最小读取为4字节,对齐),但只有4字节( uint32_t ),本机的编译器可将sizeof(char)定义为4 ? sizeof(char)将是1,但char将有32位( CHAR_BIT宏) Update2:但sizeof结果不是一个字节! 它是CHAR的大小。 char可以是2个字节,
My OpenMP program of matrix multiplication which consists of nesting of for loops is taking more execution time than the non-nested version of the parallel program. This is the block where I have used nested parallelisation. pragma omp parallel omp_set_nested(1); #pragma omp parallel for for(i=0;i<N;i++) { #pragma omp parallel for for(j=0;j<N;j++) { C[i][j]=
我的OpenMP的矩阵乘法程序包含for循环的嵌套,比并行程序的非嵌套版本花费更多的执行时间。 这是我使用嵌套并行处理的块。 杂注omp并行 omp_set_nested(1); #pragma omp parallel for for(i=0;i<N;i++) { #pragma omp parallel for for(j=0;j<N;j++) { C[i][j]=0.; // set initial value of resulting matrix C = 0 #pragma omp parallel for for(m=0;m<N
I need to convert float to int (single precision, 32 bits) like: 'float: 2 (hex: 40000000) to int: 1073741824'. Any idea how to implement that? I was looking for it in msdn help but with no result. If your aiming for versions less than .Net 4 where BitConverter isn't available, or you want to convert floats to 32 bit ints, use a memory stream: using System; using System.IO; n
我需要将float转换为int(单精度,32位),如下所示: 'float:2(hex:40000000)to int:1073741824'。 任何想法如何实现? 我在MSDN帮助中寻找它,但没有结果。 如果您针对BitNet转换器不可用的.Net 4版本进行瞄准,或者您想将浮点数转换为32位整数,请使用内存流: using System; using System.IO; namespace Stream { class Program { static void Main (string [] args) { float
I am trying to create a matrix addition program to practice with OpenMP. I have N^2 processors/threads and need to assign each thread such that it computes one entry of the resultant matrix. For example, if I have two matrices A and B of size NxN, then each thread should compute one entry of the resultant matrix C. Upon reading some of the beginner tutorials in OpenMp it seems that the #pragma
我正在尝试创建一个矩阵加法程序来练习OpenMP。 我有N ^ 2个处理器/线程,并且需要分配每个线程,以便它计算结果矩阵的一个条目。 例如,如果我有两个大小为NxN的矩阵A和B,那么每个线程都应该计算结果矩阵C的一个条目。在阅读OpenMp中的一些初学者教程时,似乎#pragma omp parallel for指令将任务同样在指定的线程总数中。 但在下面的代码中,只有3个线程处于活动状态,而不是我想要的。 我拥有的代码如下所示: #include
I am currently working on a matrix computation with OpenMP. I have several loops in my code, and instead on calling for each loop #pragma omp parallel for[...] (which create all the threads and destroy them right after) I would like to create all of them at the beginning, and delete them at the end of the program in order to avoid overhead. I want something like : #pragma omp parallel { #p
我目前正在使用OpenMP进行矩阵计算。 我在我的代码中有几个循环,而是调用每个循环#pragma omp parallel for [...](创建所有线程并在之后立即销毁它们),我想在开始时创建它们,并且在程序结束时删除它们以避免开销。 我想要这样的东西: #pragma omp parallel { #pragma omp for[...] for(...) #pragma omp for[...] for(...) } 问题是我有一些只能由一个线程执行的部分,但是在一个包含必须并行执行的
I am trying to understand pointers in C but I am currently confused with the following: char *p = "hello" This is a char pointer pointing at the character array, starting at h. char p[] = "hello" This is an array that stores hello. What is the difference when I pass both these variables into this function? void printSomething(char *p) { printf("p: %s",p); } char* and char[] are differ
我试图理解C语言中的指针,但我目前对以下内容感到困惑: char *p = "hello" 这是一个字符指针,指向字符数组,从h开始。 char p[] = "hello" 这是一个存储hello的数组。 将这两个变量传递给这个函数时有什么区别? void printSomething(char *p) { printf("p: %s",p); } char*和char[]是不同的类型,但在所有情况下都不是很明显。 这是因为数组衰减为指针,这意味着如果提供了char[]类型的表达式,其中一个类型为c
In C programming, you can pass any kind of pointer you like as an argument to free, how does it know the size of the allocated memory to free? Whenever I pass a pointer to some function, I have to also pass the size (ie an array of 10 elements needs to receive 10 as a parameter to know the size of the array), but I do not have to pass the size to the free function. Why not, and can I use this s
在C编程中,您可以将任何类型的指针作为参数传递给free,它如何知道分配的内存空间的大小? 每当我传递一个指向某个函数的指针,我还必须传递大小(即10个元素的数组需要接收10作为参数来知道数组的大小),但我不必将大小传递给免费功能。 为什么不,我可以在我自己的函数中使用这种相同的技术,以免我需要在数组长度的额外变量上使用购物车? 当你调用malloc() ,你指定了要分配的内存量。 实际使用的内存数量稍多于此,
I converted a (C#) struct into a class and need to go through all uses of the type to ensure that there are no undesired effects of the former implicit copy and now reference behaviours. Is there a way to find all references, where this specific type is used/involved? I tried Find all References on the type, and get all locations where the type name is explicitely stated, which is a good star
我将一个(C#)结构转换为一个类,并且需要通过该类型的所有用途来确保前面的隐式复制和现在引用行为没有不良影响。 有没有办法找到所有的引用,这种特定类型的使用/涉及? 我尝试过在类型上Find all References ,并获取类型名称的所有位置,这是一个好的开始。 但是,我没有得到这种类型的实例返回和修改的位置。 具体来说,我使用var将返回值赋值给隐式类型变量,或者将所有赋值赋予先前定义的变量。 有什么功能或