reference

问题 I know there are topics that are similar to this one already (such as this). The example given in this topic was this: std::string & rs1 = std::string(); Clearly, that std::string() is an rvalue. However, my question is why is s1 legal while s2 is not? const std::string& s1 = "String literal"; std::string& s2 = "String literal"; The standard clearly states that string literals are lvalues (which is understandable since they are technically const char* behind the scenes). When I compile s2

问题 I know there are topics that are similar to this one already (such as this). The example given in this topic was this: std::string & rs1 = std::string(); Clearly, that std::string() is an rvalue. However, my question is why is s1 legal while s2 is not? const std::string& s1 = "String literal"; std::string& s2 = "String literal"; The standard clearly states that string literals are lvalues (which is understandable since they are technically const char* behind the scenes). When I compile s2

问题 I know there are topics that are similar to this one already (such as this). The example given in this topic was this: std::string & rs1 = std::string(); Clearly, that std::string() is an rvalue. However, my question is why is s1 legal while s2 is not? const std::string& s1 = "String literal"; std::string& s2 = "String literal"; The standard clearly states that string literals are lvalues (which is understandable since they are technically const char* behind the scenes). When I compile s2

问题 I know there are topics that are similar to this one already (such as this). The example given in this topic was this: std::string & rs1 = std::string(); Clearly, that std::string() is an rvalue. However, my question is why is s1 legal while s2 is not? const std::string& s1 = "String literal"; std::string& s2 = "String literal"; The standard clearly states that string literals are lvalues (which is understandable since they are technically const char* behind the scenes). When I compile s2

问题 Greetings, I get the difference between pass by value and pass by reference. But pass reference (such as array) by ref and pass array by value is something i can't seem to comprehend. How can you pass a reference by reference? int[] myArray = {1,2,3}; PassByVal(myArray); PassByRef(ref myArray); PassByVal(int[] array) { array = new int[] {7,8,9}; // will not work } PassByRef(ref int[] array) { array = new int[] {10,11,12}; } // will work 回答1: I suggest that you check out this link. It's quite

问题 Greetings, I get the difference between pass by value and pass by reference. But pass reference (such as array) by ref and pass array by value is something i can't seem to comprehend. How can you pass a reference by reference? int[] myArray = {1,2,3}; PassByVal(myArray); PassByRef(ref myArray); PassByVal(int[] array) { array = new int[] {7,8,9}; // will not work } PassByRef(ref int[] array) { array = new int[] {10,11,12}; } // will work 回答1: I suggest that you check out this link. It's quite

问题 std::tie(a, b) = std::minmax(a, b); I think this is intuitive code. Clean and understandable. Too bad it doesn't work as intended, as std::minmax templates for const& . If therefore the values are swapped inside the std::pair<const&, const&> than one assignement will overwrite the other value: auto[a, b] = std::make_pair(7, 5); std::tie(a, b) = std::minmax(a, b); std::cout << "a: " << a << ", b: " << b << '\n'; a: 5, b: 5 The expected output here is a: 5, b: 7 . I think this is important as

问题 Is there a tool or method to locate strong references cycles in my SWIFT code? A strong reference cycle is when two instances of classes reference each other without the proper safeties ( weak / unowned ) hence preventing the garbage collector from disposing of them once all the variables I created stopped referencing those objects. 回答1: The method for finding strong reference cycles is the same in Swift as it is in Objective-C. You'd run the app from Xcode, exercise the app sufficiently to

问题 I want to build a sublist with references to the elements of anoter list (i need few of them, that are meeting the conditions). How am i trying to do that: List<int> mainList = new List<int>(); List<int> subList = new List<int>(); mainList.Add(5); subList.Add(mainList[0]); //case 1 //subList[0] = mainList[0]; //case 2 Console.WriteLine("{0}", mainList[0]); Console.WriteLine("{0}", subList[0]); subList[0]++; Console.WriteLine("{0}", mainList[0]); Console.WriteLine("{0}", subList[0]); mainList

问题 For the sake of code readability, I'd like to move my Excel stuff to a function and leave the worksheet object available to write cell values as my program processes stuff. How do I call a function that creates an Excel spreadsheet and return a worksheet reference so I can continue to access the open/active Excel app object I've created? Function Create-Excel-Spreadsheet() { # open excel $excel = New-Object -ComObject excel.application $excel.visible = $True # add a worksheet $workbook =