这两句代码有什么区别，为什么前者报错？

[w7]

消息处理函数中：

	switch (uMsg)
	{	case WM_PAINT:
		PAINTSTRUCT ps;
		HDC hDC = BeginPaint(hWnd, &ps);  //有错：不能编译	error C2360: “hDC”的初始化操作由“case”标签跳过

		TextOut(hDC, 0, 0, TEXT("HELLO"), 2);
		EndPaint(hWnd, &ps);
		break;

为什么把那一句分成两句就没可以编译了？

		HDC hDC;
		hDC = BeginPaint(hWnd, &ps);

[真相重于对错]

c++ 了解一下变量的作用域

[schlafenhamster]

Compiler Error C2360 initialization of 'identifier' is skipped by 'case' label The specified identifier initialization can be skipped in a switch statement. It is illegal to jump past a declaration with an initializer unless the declaration is enclosed in a block. The scope of the initialized variable lasts until the end of the switch statement unless it is declared in an enclosed block within the switch statement. The following is an example of this error: void func( void ) { int x; switch ( x ) { case 0 : int i = 1; // error, skipped by case 1 { int j = 1; } // OK, initialized in enclosing block case 1 : int k = 1; // OK, initialization not skipped } }

[Eleven]

case语句下面用{}包起来即可。

[zhuyf87]

switch ( expression ) case constant-expression : statement An inner block of a switch statement can contain definitions with initializations as long as they are reachable — that is, not bypassed by all possible execution paths. Names introduced using these declarations have local scope. For example:

// switch_statement2.cpp
// C2360 expected
#include <iostream>
using namespace std;
int main(int argc, char *argv[])
{
   switch( tolower( *argv[1] ) )
   {
       // Error. Unreachable declaration.
       char szChEntered[] = "Character entered was: ";
   
   case 'a' :
       {
       // Declaration of szChEntered OK. Local scope.
       char szChEntered[] = "Character entered was: ";
       cout << szChEntered << "a\n";
       }
       break;
   
   case 'b' :
       // Value of szChEntered undefined.
       cout << szChEntered << "b\n";
       break;
   
   default:
       // Value of szChEntered undefined.
       cout << szChEntered << "neither a nor b\n";
       break;
   }
}

[worldy]

你是c代码，c代码的必须将变量定义放在函数的开头，不能使用 HDC hDC =...；的语法 必须HDC hDC ； hDC=...；

[hushoubo]

引用 3 楼 VisualEleven 的回复:

case语句下面用{}包起来即可。

正解....

[w7]

加上{}是可以，但是为什么不加就不对呢，谁能用中文解释下？

[zhuyf87]

http://msdn.microsoft.com/zh-tw/library/61af7cx3(v=vs.71).aspx

[paldier]

楼上已经很多人解释了，请逐行逐字的看几遍

[parachutes30]

变量的定义可能会被switch的case分句跳过去，别的case分句就看不到这个定义了，所以编译器不允许这样做。

[rxguoblp]

对于switch-case;用{}包起来每一个case的处理代码并且不要漏掉"default:break;"是一个好习惯。

[boylafong]

变量作用域 case下面没有{} 是不能定义的