处理整数溢出在C＃中的最佳方法是什么？ [英] Best way to handle Integer overflow in C#?

问题描述

处理整数溢出是一种常见的任务，但什么是处理在C＃中的最佳方法是什么？有一些语法糖，使其比其他语言更简单？还是这真的是最好的方法是什么？

  INT X = FOO（）;
INT试验= X *常见;
如果（测试/常见！= X）
    Console.WriteLine（哦不一！）;
其他
    Console.WriteLine（安全！）;
 

解决方案

我还没有使用这种经常需要的，但你可以使用的checked 关键字：

  INT X = FOO（）;
INT测试=检查（X *常见）;
 

将导致运行时异常，如果溢出。从MSDN：

在checked上下文中，如果前女友pression产生的值是目标类型的范围之外时，结果取决于EX pression是否恒定或不恒定的恒恩pressions导致编译时错误，而非常量的前pressions在运行时评估并引发异常。

我还应该指出的是，还有另外一个C＃的关键字，选中，这当然不相反检查并忽略溢出。你可能不知道，当你曾经使用选中，因为它似乎是默认的行为。那么，有一个定义如何EX pressions外检查和选中正在处理的C＃编译器选项： /检查。您可以设置它在你的项目的高级构建设置。

如果你有很多需要进行检查前pressions，做最简单的做法实际上是将 /检查构建选项。那么任何EX pression溢出，除非包裹在选中，将导致运行时异常。

Handling integer overflow is a common task, but what's the best way to handle it in C#? Is there some syntactic sugar to make it simpler than with other languages? Or is this really the best way?

int x = foo();
int test = x * common;
if(test / common != x)
    Console.WriteLine("oh noes!");
else
    Console.WriteLine("safe!");

解决方案

I haven't needed to use this often, but you can use the checked keyword:

int x = foo();
int test = checked(x * common);

Will result in a runtime exception if overflows. From MSDN:

"In a checked context, if an expression produces a value that is outside the range of the destination type, the result depends on whether the expression is constant or non-constant. Constant expressions cause compile time errors, while non-constant expressions are evaluated at run time and raise exceptions."

I should also point out that there is another C# keyword, unchecked, which of course does the opposite of checked and ignores overflows. You might wonder when you'd ever use unchecked since it appears to be the default behavior. Well, there is a C# compiler option that defines how expressions outside of checked and unchecked are handled: /checked. You can set it under the advanced build settings of your project.

If you have a lot of expressions that need to be checked, the simplest thing to do would actually be to set the /checked build option. Then any expression that overflows, unless wrapped in unchecked, would result in a runtime exception.

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