organize project and specify directory for object files in Makefile

Here are my two questions: I am now learning to manage my code with CVS, and I just want to make a repository for my C++ files, Makefile and bash and python scripts only, not the object files and executables. So I made several subdirectories under my project directory: src, bin, scripts, results and data. I put C++ files and Makefile under ~/myproject/src, bash and python scripts under ~/mypr

组织项目并在Makefile中指定目标文件的目录

这是我的两个问题: 我现在正在学习使用CVS管理我的代码,我只想为我的C ++文件,Makefile和bash和python脚本创建一个存储库,而不是目标文件和可执行文件。 所以我在我的项目目录下创建了几个子目录:src,bin,脚本,结果和数据。 我将?/ myproject / src下的C ++文件和Makefile,?/ myproject / scripts下的bash和python脚本以及?/ myproject / bin下的对象和可执行文件放在一起。 我希望只有src和脚本下的文件会通过

Hashing polymorphic type the proper way

I have a hash process implemented using Howard Hinnant's method (generic hash based on hash_append overloads). The purpose of that method is to create hash of classes in order to "memoize" result of computations (see end of this answer), so I am facing some issue. In particular, consider the following possible Input class that needs to be hashed: struct A { virtual int do_st

散列多态类型是正确的方式

我有一个使用Howard Hinnant方法实现的哈希过程(基于hash_append重载的泛型哈希)。 该方法的目的是为了“记忆”计算结果而创建类的散列(参见本答案的结尾),所以我正面临一些问题。 特别是,请考虑以下可能的需要进行散列的Input类: struct A { virtual int do_stuff() const = 0; virtual ~A(); }; struct B: A { int do_stuff() const override { return 0; } }; struct C: A { const int u; int d

reading and writing to QProcess in Qt Console Application

Noted: this appears to be a specific issue question but hopefully it can be edited for all to related to I need to interact with a QProcess object. The Problem: I am not getting any output from QProcess after calling QProcess:write(input) More Info: Going through the doc pages led me to create an example below: I have a script requesting user input, and finally displaying and appropri

在Qt控制台应用程序中读取和写入QProcess

注意:这似乎是一个具体的问题,但希望它可以编辑为所有相关 我需要与QProcess对象进行交互。 问题: 在调用QProcess:write(input)之后,我没有从QProcess获得任何输出QProcess:write(input) 更多信息: 阅读文档页面让我在下面创建一个示例: 我有一个请求用户输入的脚本,最后根据用户输入显示和适当的消息。 测试: 将“日志”功能添加到我的脚本进行测试后,会发生以下情况: 脚本执行 脚本请求用户输入(

Constexpr conditions for constructor

On this site, it is specified that: "A constexpr function must satisfy the following requirements: [...] there exists at least one set of argument values such that an invocation of the function could be an evaluated subexpression of a core constant expression ( for constructors, use in a constant initializer is sufficient ) (since C++14). No diagnostic is required for a violation of t

构造函数的Constexpr条件

在这个网站上,它指定: “一个constexpr函数必须满足以下要求: [...] 至少存在一组参数值,使得函数的调用可以是核心常量表达式的评估子表达式( 对于构造函数,在常量初始化器中使用就足够了 )(自C ++ 14以来)。 违反此项规定不需要诊断。“ 粗体语句的含义是什么? 查看链接的缺陷报告 struct X { std::unique_ptr p; constexpr X() { } }; 在C ++ 14之前,这会因[dcl.constexpr] 对于co

Templated Sum(Args...) variadic function doesn't compile

I used static struct member trick to enforce 2nd pass compilation and still get an error: struct S { template static T Sum(T t) { return t; } template static auto Sum(T t, Rest... rest) -> decltype(t + Sum(rest...) ) { return t + Sum(rest...); } }; int main() { auto x = S::Sum(1,2,3,4,5)

模板化Sum(Args ...)可变参数函数不能编译

我使用静态结构成员技巧强制执行第二遍编译,但仍然出现错误: struct S { template static T Sum(T t) { return t; } template static auto Sum(T t, Rest... rest) -> decltype(t + Sum(rest...) ) { return t + Sum(rest...); } }; int main() { auto x = S::Sum(1,2,3,4,5); } main.cpp:17:14:没有用

How to get NDK debugging to work in Android Studio?

Android Studio doesn't stop at breakpoints in C++ code, this is what i've done so far : In AndroidManifest.xml : android:debuggable="true" In build.gradle (this may be the problem): sourceSets.main { jniLibs.srcDir 'src/main/libs' jni.srcDirs = [] } task ndkBuild(type: Exec) { commandLine android.ndkDirectory.getAbsolutePath() + '\' + 'ndk-build.cmd', '-C', file('src/main/jni'

如何让NDK调试在Android Studio中工作?

Android Studio不会停留在C ++代码的断点处,这是我迄今为止所做的: 在AndroidManifest.xml中: android:debuggable="true" 在build.gradle(这可能是问题): sourceSets.main { jniLibs.srcDir 'src/main/libs' jni.srcDirs = [] } task ndkBuild(type: Exec) { commandLine android.ndkDirectory.getAbsolutePath() + '\' + 'ndk-build.cmd', '-C', file('src/main/jni').absolutePath, 'NDK_DEBUG=1' } tasks.w

C++ random float number generation

How do I generate random floats in C++? I thought I could take the integer rand and divide it by something, would that be adequate enough? rand() can be used to generate pseudo-random numbers in C++. In combination with RAND_MAX and a little math, you can generate random numbers in any arbitrary interval you choose. This is sufficient for learning purposes and toy programs. If you need tru

C ++随机浮点数生成

如何在C ++中生成随机的浮点数? 我想我可以把整数兰德分成几个等级,这足够吗? rand()可用于在C ++中生成伪随机数。 结合RAND_MAX和一些小数学运算,您可以根据您选择的任意间隔生成随机数。 这对于学习目的和玩具程序已经足够了。 如果您需要正态分布的真正随机数字,则需要采用更高级的方法。 这将生成一个从0.0到1.0的数字。 float r = static_cast (rand()) / static_cast (RAND_MAX

How to easily convert an unsigned string to a string?

I define an unsigned string as a string containing unsigned chars: namespace std { typedef basic_string ustring; } Thus, given a basic std::string whose chars range from -128 to 127, how can I easily convert it to a std::ustring whose chars range from 0 to 255? 你可以使用迭代器构造函数: ustring to_ustring(const std::string& s) { return {s.begin(), s.end()}; }

如何轻松将无符号字符串转换为字符串?

我将一个无符号字符串定义为一个包含无符号字符的字符串: namespace std { typedef basic_string ustring; } 因此,给定一个基本的std::string其字符范围从-128到127,我怎样才能轻松地将它转换为std::ustring其字符范围从0到255? 你可以使用迭代器构造函数: ustring to_ustring(const std::string& s) { return {s.begin(), s.end()}; } 你做: using ustring = std::vector<>

When would you use "signed char" over "unsigned char"?

To my knowledge, there isn't much of a difference between an unsigned char and a signed char besides a signed char ranging from -127 to 128 and an unsigned char ranging from 0 to 255. I'm trying to learn C++ and I've been wondering this for a while. Also, I was a lua programmer for a long time so I'm used to unsigned chars, so I'm just wondering the difference and when you

你什么时候使用“signed char”而不是“unsigned char”?

据我所知,没有太多的之差的unsigned char和signed char ,除了一个符号字符的范围从-127到128和无符号的字符范围从0到255,我想学C ++和我我一直在想这个。 另外,我很久以前就是一个lua程序员,所以我习惯于未签名的字符,所以我只是想知道它们的区别,以及何时使用带符号的字符而不使用unsigned char。 谢谢。 正如@SomeProgrammerDude所解释的,你已经知道,当你希望使用小的整数值时,你明确地指定了signed或unsigned

C++ char type length and size

hello i have some questions about c++ variable type (char). i read in some sites that this char support range from (-128 to 127) and in unsigned (0 to 255). what is this mean? char support not just numbers so why they say (-128 to 127) ? what mean this range ?? range for what? my other question is: when i can use this const char * Data; Data = "ddddddddddddddddddddddddddddddddddddddd

C ++字符类型的长度和大小

你好我有一些关于c ++变量类型(char)的问题。 我读过一些网站,这个字符支持范围从(-128到127)和无符号(0到255)。 这是什么意思? char不仅支持数字,他们为什么说(-128到127)? 这个范围是什么意思? 什么范围? 我的另一个问题是:当我可以使用这个 const char * Data; Data = "dddddddddddddddddddddddddddddddddddddddddddddddde21312313ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd