declaration

问题 std::is_function is specialized for types which have signature similar to: int(int) & see here:std::is_function But this is neither a pointer to a member method, which signature could be: int(T::*)(int) & Nor it can be a reference to a function: int (&)(int) So what is this strange signature? 回答1: It's a function type which only exists in the type system. It cannot ever be created. But this is neither a pointer to a member method, which signature could be: int(T::*)(int) & It's this, without

问题 std::is_function is specialized for types which have signature similar to: int(int) & see here:std::is_function But this is neither a pointer to a member method, which signature could be: int(T::*)(int) & Nor it can be a reference to a function: int (&)(int) So what is this strange signature? 回答1: It's a function type which only exists in the type system. It cannot ever be created. But this is neither a pointer to a member method, which signature could be: int(T::*)(int) & It's this, without

问题 In what way are these statements different? double dummy = 0; double dummy = 0.0; double dummy = 0.0d; double dummy = 0.0D; 回答1: Having tried a simple program (using both 0 and 100, to show the difference between "special" constants and general ones) the Sun Java 6 compiler will output the same bytecode for both 1 and 2 (cases 3 and 4 are identical to 2 as far as the compiler is concerned). So for example: double x = 100; double y = 100.0; compiles to: 0: ldc2_w #2; //double 100.0d 3: dstore

问题 In what way are these statements different? double dummy = 0; double dummy = 0.0; double dummy = 0.0d; double dummy = 0.0D; 回答1: Having tried a simple program (using both 0 and 100, to show the difference between "special" constants and general ones) the Sun Java 6 compiler will output the same bytecode for both 1 and 2 (cases 3 and 4 are identical to 2 as far as the compiler is concerned). So for example: double x = 100; double y = 100.0; compiles to: 0: ldc2_w #2; //double 100.0d 3: dstore

问题 From what I have understood, declarations/initializations in C++ are statements with 'base type' followed by a comma separated list of declarators. Consider the following declarations: int i = 0, *const p = &i; // Legal, the so-called base type is 'int'. // i is an int while p is a const pointer to an int. int j = 0, const c = 2; // Error: C++ requires a type specifier for all declarations. // Intention was to declare j as an int and c an as const int. int *const p1 = nullptr, i1 = 0; // p1

问题 I created this program and C# and it worked correctly a few weeks ago. Now, I copied all of this code to a another project I am working on. I added it to a brand new C# Class inside of the project I am working on. Visual Studio didn't recognize the assembly references that say "not found" in the comments. This is just bizarre since they were found in the previous program. Does anyone know why Visual Studio can't find these assembly references. using System; using System.Collections.Generic;

问题 I was just going through some code on the Internet and found this: float * (*(*foo())[SIZE][SIZE])() How do I read this declaration? Is there a specific set of rules for reading such complex declarations? 回答1: I haven't done this in a while! Start with foo and go right. float * (*(* foo() )[SIZE][SIZE])() foo is a function with no arguments... Can't go right since there's a closing parenthesis. Go left: float * (*( * foo() )[SIZE][SIZE])() foo is a function with no arguments returning a

问题 I've been using the Eclipse IDE for a few years now. When programming in C I'm used to Ctrl+Click on a symbol and Eclipse takes me to the file and line of the symbol's declaration. Without an IDE, how do I achieve this? I'm using gcc to compile a massive FOSS project with hundreds of header files. Looking though the C files, I see functions that I would like to know more about. Finding the header file that declares said function is a tedious and manual task. Not to mention manual

问题 I'm trying to learn C language for embedded systems. At the moment I'm learning the basics and couldn't find an answer to one of a fundamental question. When I wrote a simple C program I declared a function called maximum() in three ways. I will explain it by the following examples: 1-) Here in the below program the function is declared outside and before the main: #include <stdio.h> int maximum(int x, int y) { int z; z = (x >= y) ? x : y; return z; } int main(void) { int result = maximum(30,

问题 For example, I often see this: Set<Integer> s = new TreeSet<Integer>(); Set<Integer> s = new HashSet<Integer>(); Map<Integer, String> m = new HashMap<Integer, String>(); over TreeSet<Integer> ts = new TreeSet<Integer>(); HashSet<Integer> hs = new HashSet<Integer>(); HashMap<Integer, String> hm = new HashMap<Integer, String>(); What are the advantages/disadvanges of the former vs the latter? 回答1: For me it comes down to a number of points. Do you care about the implementation? Does your code