reference

问题 Iv got to the stage in my c++ study concerning references. It states the following rule: Once a reference is initialized to an object, it cannot be changed to refer to another object. Iv wrote a short code (as asked to in an exercise) that is meant to prove this rule correct. int y = 7; int z = 8; int&r = y; r = z; Can someone explain why this code compiles without any errors or warnings? 回答1: r = z does not change what r "points to." It assigns the value of z to the object pointed to by r .

问题 I am having troubles adding the excel reference to my project. I have already installed Primary Interop Assemblies. The project is detecting the Microsoft.Office.Interop.Word assembly reference correctly but the excel reference still cannot be found. When I try to manually add the reference, I right click the project, add reference, navigate to the Microsoft.Office.Interop.Excel file and try to add it manually. Once i select the reference I then make sure the reference is checked, then hit ok

问题 How does a handle differ from a pointer to an object and also why can't we have a reference to a reference? 回答1: A handle is usually an opaque reference to an object. The type of the handle is unrelated to the element referenced. Consider for example a file descriptor returned by open() system call. The type is int but it represents an entry in the open files table. The actual data stored in the table is unrelated to the int that was returned by open() freeing the implementation from having

问题 I've tried to code like this several times: struct Foo { double const& f; Foo(double const& fx) : f(fx) { printf("%f %f\n", fx, this->f); // 125 125 } double GetF() const { return f; } }; int main() { Foo p(123.0 + 2.0); printf("%f\n", p.GetF()); // 0 return 0; } But it doesn't crash at all. I've also used valgrind to test the program but no error or warning occured. So, I assume that the compiler automatically generated a code directing the reference to another hidden variable. But I'm

问题 I've tried to code like this several times: struct Foo { double const& f; Foo(double const& fx) : f(fx) { printf("%f %f\n", fx, this->f); // 125 125 } double GetF() const { return f; } }; int main() { Foo p(123.0 + 2.0); printf("%f\n", p.GetF()); // 0 return 0; } But it doesn't crash at all. I've also used valgrind to test the program but no error or warning occured. So, I assume that the compiler automatically generated a code directing the reference to another hidden variable. But I'm

问题 Quoting MSDN - const (C# reference): A constant expression is an expression that can be fully evaluated at compile time. Therefore, the only possible values for constants of reference types are string and a null reference. According to: typeof(T) vs. Object.GetType() performance, typeof(T) is a compile time expression. So why can't a Type be a constant value? The following code will not compile: public const Type INT_TYPE = typeof(int); 回答1: Constants are substituted by the compiler with

问题 In school, our lecturer taught us that the entire array was passed by reference when we pass it to a function,. However, recently I read a book. It says that arrays are passed by pointer by default when passing the entire array to a function. The book further mention that " passing by pointer is very similar to passing by reference ", which means that passing by pointer and passing by reference are actually different. It appears that different source stated differently. So my question is: In

问题 In school, our lecturer taught us that the entire array was passed by reference when we pass it to a function,. However, recently I read a book. It says that arrays are passed by pointer by default when passing the entire array to a function. The book further mention that " passing by pointer is very similar to passing by reference ", which means that passing by pointer and passing by reference are actually different. It appears that different source stated differently. So my question is: In

问题 I am using eConnect SDK 11.0. I have a windows service app in which i had added reference of GP sdk. 1) Microsoft.Dynamics.GP.eConnect.dll 2) Microsoft.Dynamics.GP.eConnect.Serialization.dll When i build my project it had built successfully but gave me the following warning 1) There was a mismatch between the processor architecture of the project being built "MSIL" and the processor architecture of the reference "Microsoft.Dynamics.GP.eConnect, Version=11.0.0.0, Culture=neutral,

问题 I am using eConnect SDK 11.0. I have a windows service app in which i had added reference of GP sdk. 1) Microsoft.Dynamics.GP.eConnect.dll 2) Microsoft.Dynamics.GP.eConnect.Serialization.dll When i build my project it had built successfully but gave me the following warning 1) There was a mismatch between the processor architecture of the project being built "MSIL" and the processor architecture of the reference "Microsoft.Dynamics.GP.eConnect, Version=11.0.0.0, Culture=neutral,