declaration | 易学教程

Missing partial modifier on declaration ..another partial declaration of this type exists". I'm a beginner and just following the book

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问题 I'm a beginner and I'm doing an exercise following a book. Below is my code and i got this "Missing partial modifier on declaration of type 'Windowsform.Form1'; another partial declaration of this type exists" . What should i do? My code is as follows: using System; using System.Windows.Forms; namespace Windowsform { public class Form1 : Form { private TextBox txtEnter; private Label lblDisplay; private Button btnOk; public Form1() { this.txtEnter = new TextBox(); this.lblDisplay = new Label(

Getting error: ISO C++ forbids declaration of with no type

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I'm getting the following errors: ISO C++ forbids declaration of ttTreeInsert with no type ISO C++ forbids declaration of ttTreeDelete with no type ISO C++ forbids declaration of ttTreePrint with no type prototype for int ttTree::ttTreePrint() does not match any in class ttTree candidate is: void ttTree::ttTreePrint() Here is my header file: #ifndef ttTree_h #define ttTree_h class ttTree { public: ttTree(void); int ttTreeInsert(int value); int ttTreeDelete(int value); void ttTreePrint(void); }; #endif Here is my .cpp file: #include "ttTree.h" ttTree::ttTree(void) { } ttTree::ttTreeInsert(int

Why does c++ pointer * associate to the variable declared, not the type?

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问题 Why was C++ designed such that the correct way to declare two int *s on the same line is int *x, *y; not int* x,y; I know some people think you should avoid either form and declare every variable on its own line, but I'm interested in why this language decision was made. 回答1: To keep compatibility with C code, because that's how C works. Bjarne makes a good point here: The choice between int* p; and int *p; is not about right and wrong, but about style and emphasis. C emphasized expressions;

Get variable (not hard-coded) name?

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I am looking for a way to retrieve the variable name, so I don't have to use hard-coded declarations when needed (for property names etc.): I hardly believe it's possible; maybe someone has a solution. Note: even not variables, properties would also be a move. 'Pseudo: Module Module1 Sub Main() Dim variable = "asdf" Dim contact As New Contact Dim v1 = GetVariableName(variable) 'returns variable Dim v2 = GetVariableName(contact.Name) 'returns Name End Sub Class Contact Public ReadOnly Property Name() Get Return Nothing End Get End Property End Class Public Function GetVariableName(variable As

PHP: how to avoid redeclaring functions?

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问题 I tend to get errors such as: Fatal error: Cannot redeclare get_raw_data_list() (previously declared in /var/www/codes/handlers/make_a_thread/get_raw_data_list.php:7) in /var/www/codes/handlers/make_a_thread/get_raw_data_list.php on line 19 how can I avoid the error? Is it possible to create a IF-clause to check whether a function is declared before declaring it? 回答1: Use require_once or include_once as opposed to include or require when including the files that contain your functions. The

Why did C++ never allow functions to be used before they're declared? [closed]

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问题 Closed . This question is opinion-based. It is not currently accepting answers. Want to improve this question? Update the question so it can be answered with facts and citations by editing this post. Closed 5 years ago . OK, I know this looks like a duplicate of Why do functions need to be declared before they are used? but it doesn't seem like existing answers fully address all the details. I know that C++ was originally designed in the 80's so it could be translated in a single pass,

Is there a difference between int x and int x in C++? [duplicate]

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问题 This question already has an answer here : Difference between char* var; and char *var;? [duplicate] (1 answer) Closed 6 years ago . I'm getting back into my C++ studies, and really trying to understand the basics. Pointers have always given me trouble, and I want to make sure I really get it before I carry on and get confused down the road. Sadly, I've been stymied at the very outset by an inconsistency in the tutorials I'm reading. Some do pointer declarations this way: int *x and some do

How do I write a TypeScript declaration file for an external commonjs module that has constructor?

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PLEASE SEE MORE DETAILED QUESTION: How do I write a TypeScript declaration file for a complex external commonjs module that has constructor, such as imap? I write TypeScript for a Node.js app, and I want to write a TypeScript declaration file for a javascript module (available from npm) that has a constructor at the module level. Here is a simplified version of the relevant code, in file a.js : function A(config) { this.state = 'constructed'; } A.prototype.update = function() { this.state = 'updated'; }; module.exports = A; and a simplified javascript application, app.js , that uses module a :

Why doesn't C# let you declare multiple variables using var?

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问题 Given the following: // not a problem int i = 2, j = 3; so it surprises me that this: // compiler error: Implicitly-typed local variables cannot have multiple declarators var i = 2, j = 3; doesn't compile. Maybe there is something I don't understand about this (which is why I'm asking this)? But why wouldn't the compiler realize that I meant: var i = 2; var j = 3; which WOULD compile. 回答1: It's just another point of possible confusion for the programmer and the compiler. For example this is

Program with chaining of using-declarations compiles on MSVS and clang but not on GCC

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问题 Is the following program well-formed or ill-formed according to the c++ standard? namespace X { int i; } namespace Y { using X::i; } int main() { using X::i; using Y::i; } I'm getting different results with different compilers: MSVS: Compiles ( http://webcompiler.cloudapp.net/ ) Clang: Compiles ( http://melpon.org/wandbox/permlink/KloDufJ5h1DalK4v ) GCC: Compile error ( http://melpon.org/wandbox/permlink/IKuuQGE1THofuUTr ) I don't want to fix this program to make it compile on GCC. I just