问题描述

处理整数溢出是一项常见任务，但在 C# 中处理它的最佳方法是什么?是否有一些语法糖使它比其他语言更简单?或者这真的是最好的方法吗?

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!");

推荐答案

我不需要经常使用这个，但是你可以使用 checked 关键字:

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

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

如果溢出将导致运行时异常.来自 MSDN:

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

在检查的上下文中，如果表达式产生的值是在目标类型范围之外，结果取决于表达式是常量还是非常量.持续的表达式导致编译时错误，而非常量表达式在运行时进行评估并引发异常.

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.

我还应该指出，还有另一个 C# 关键字，unchecked，它当然与 checked 相反并且忽略溢出.您可能想知道您何时使用过 unchecked，因为它似乎是默认行为.好吧，有一个 C# 编译器选项定义了如何处理 checked 和 unchecked 之外的表达式:/checked.您可以在项目的高级构建设置下进行设置.

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.

如果您有很多表达式需要检查，最简单的做法实际上是设置 /checked 构建选项.那么任何溢出的表达式，除非包含在 unchecked 中，都会导致运行时异常.

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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