在Visual Basic .NET C风格的指针 [英] C-style pointer in Visual Basic .NET

问题描述

我一直在调查在Visual Basic .NET C风格的指针有一段时间了。我所遇到的 http://support.microsoft.com/kb/199​​824?wa = wsignin1.0 ，但我不知道如果这是正确的事情还是如何应用它。我已经用C语言编写的程序使用一个简单的指针，我想它转换线线到Visual Basic与评论在必要。
这里是C：

  INT的main（）
{
    为int *为mynumber = 3; //将*意味着它是一个指针    doubleIt（*为mynumber）; //我们使用虚空中，*意味着它返回一个值没有解决
    的printf（％D，mynumber的）; //我们打印变量    返回0; //我们终止功能
}无效doubleIt（INT输入）
{
    输入* = 2; //双输入
}
 

解决方案

有一些问题，你的C code，其中之一是这样的：

 为int *为mynumber = 3; //将*意味着它是一个指针
 

您不能赋值给这样一个指针，没有首先分配内存吧。

所以，你会做到以下几点：

 为int * mynumber的malloc的=（的sizeof（INT））;
*为mynumber = 3;
免费（mynumber的）;
 

VB.NET没有指针的概念。一切（即每对象）是一个参考，这是约接近三分球，将得到不使用互操作。如果你需要做的互操作还有的的IntPtr 键入可用于重新present指针类型。

您VB.NET程序可能看起来像这样：（原谅我，如果语法不完全正确的，它已经有一段时间）

 副主
    昏暗mynumber的作为整数= 3
    doubleIt（mynumber的）
    Console.WriteLine（mynumber的）
结束小组子doubleIt（VAL的ByRef作为整数）
    VAL * = 2
结束小组
 

I have been investigating C-style pointers in Visual Basic .NET for a while now. I have come across http://support.microsoft.com/kb/199824?wa=wsignin1.0 but I have no idea if that is the right thing or how to apply it. I have written a simple pointer using program in c and I would like it converted line for line into Visual Basic with comments wherever necessary. Here's the C:

int main()
{
    int *myNumber=3; //the * means it's a pointer

    doubleIt(*myNumber); //we use the void, the * means it returns a value not address
    printf("%d",myNumber); //we print the variable

    return 0; //we terminate the function
}

void doubleIt(int input)
{
    input*=2; //double the input
}

解决方案

There's some issues with your C code, one of them being this:

int *myNumber=3; //the * means it's a pointer  

You cannot assign a value to a pointer like that, without first allocating memory to it.

So you would do the following:

int* myNumber = malloc(sizeof(int));
*myNumber  = 3;
free(myNumber);

VB.NET has no notion of pointers. Everything (ie every Object) is a reference, and that's about as close to pointers it will get without using Interop. If you need to do interop there's the IntPtr type which can be used to represent a pointer type.

Your VB.NET program might look something like this: (forgive me if the syntax isn't exactly correct, it's been a while)

Sub Main
    Dim myNumber As Integer = 3
    doubleIt(myNumber)
    Console.WriteLine(myNumber)
End Sub

Sub doubleIt(ByRef val As Integer)
    val *= 2
End Sub

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