declaration

问题 I have class NumberArray in NumberArray.h class NumberArray { private: double *aPtr; int arraySize; public: NumberArray(int size, double value); // ~NumberArray() { if (arraySize > 0) delete [ ] aPtr;} //commented out to avoid problems with the //default copy constructor void print() const; void setValue(double value); }; When I go to write the print function in NumberArray.cpp void NumberArray::print() { for (int index = 0; index < arraySize; index++) cout << aPtr[index] << " "; } It gives

问题 I have class NumberArray in NumberArray.h class NumberArray { private: double *aPtr; int arraySize; public: NumberArray(int size, double value); // ~NumberArray() { if (arraySize > 0) delete [ ] aPtr;} //commented out to avoid problems with the //default copy constructor void print() const; void setValue(double value); }; When I go to write the print function in NumberArray.cpp void NumberArray::print() { for (int index = 0; index < arraySize; index++) cout << aPtr[index] << " "; } It gives

问题 what could be a possible use of declaring types within a namespace but not in a class. For ex: namespace Test { public delegate void Ispossible(); } This is valid & does not generate any compilation errors but i can't think of why we would declare it this way as opposed to inside a class. 回答1: A namespace is a high-level unit of organization within .NET. Declaring types within classes is typically frowned upon (but, as with all things, it's not a 100% rule) because it can make the types more

问题 I wonder if the declaration order of a function in a header has an importance. Let's imagine : I've got two projects that use the same header definition, and the header had to be copied for some obscure reason. And these headers are not the same in terms of declaration function order. So the header for my first project would be : class A { someFunctionA(); someFunctionB(); } and the header in the second project : class A { someFunctionB(); someFunctionA(); } And now what will happen if I use

问题 I am writing a c++ code and my need is to declare a class having two elments as class arr{ public: long num; string str; }; now i need to store almost 1000000 elments of this class(depending on user input number of class object can warry in a range of 1 <= n <= 1000000 The object are created dynamically as #include <iostream> #include<string> using namespace std; class arr{ public: long i; string str; }; int main(){ long n,j,i; cin>>n; arr a[n]; .... rest of programme but if value of n is

问题 This is a followup to C++ templates: prevent instantiation of base template I use templates to achieve function overloading without the mess of implicit type conversions: declare the function template, define desired specializations (overloads). all is well except wrong code does not produce errors until the link phase: lib.hpp: template<class T> T f(T v); lib.cpp: #include "lib.hpp" template<> long f(long v) { return -v; } template<> bool f(bool v) { return !v; } main.cpp: #include <iostream

问题 I am trying to build a model that will have slightly different equations based on whether or not certain components exist (in my case, fluid ports). A code like the following will not work: parameter Boolean use_component=false; Component component if use_component; equation if use_component then component.x = 0; end if; How can I work around this? 回答1: If you want to use condition components, there are some restrictions you need to be aware of. Section 4.4.5 of the Modelica 3.3 specification

问题 I am trying to build a model that will have slightly different equations based on whether or not certain components exist (in my case, fluid ports). A code like the following will not work: parameter Boolean use_component=false; Component component if use_component; equation if use_component then component.x = 0; end if; How can I work around this? 回答1: If you want to use condition components, there are some restrictions you need to be aware of. Section 4.4.5 of the Modelica 3.3 specification

问题 I am programming a graph using a list of lists. For that, I have two classes, and each one of this classes has a pointer to another object of the same class and a pointer to the object of the second class. Here is the code: File V.h: #ifndef VERTICEPUNT_H #define VERTICEPUNT_H #include "A.cpp" typedef char E; class V { public: E etiqueta; V* siguiente; A* primera; //<- Error: 'A' does not name a type V(); ~V(); }; #endif // VERTICEPUNT_H File V.cpp: #include "V.h" V::V() { etiqueta = ' ';

问题 As far as I know, in C# all fields are private for default, if not marked otherwise. class Foo { private string bar; } class Foo { string bar; } I guess these two declarations are equal. So my question is: what for should I mark private variables as private if they already are private? 回答1: I've been on the fence for a while about this. I used to argue for leaving it implicit, but now I think I'm tipped over towards making it explicit. Reasons for leaving it implicit: It means there's a