C++核心准则ES.103​:防止溢出​

2020-06-17 19:10:49 浏览数 (2)

ES.103: Don't overflow

ES.103:防止溢出

Reason(原因)

Overflow usually makes your numeric algorithm meaningless. Incrementing a value beyond a maximum value can lead to memory corruption and undefined behavior.

溢出通常会导致数字算法失去意义。超过最大值的增量运算会导致内存破坏和无定义的行为。

Example, bad(反面示例)

代码语言:javascript复制
int a[10];
a[10] = 7;   // bad

int n = 0;
while (n   < 10)
    a[n - 1] = 9; // bad (twice)
Example, bad(反面示例)
代码语言:javascript复制
int n = numeric_limits<int>::max();
int m = n   1;   // bad
Example, bad(反面示例)
代码语言:javascript复制
int area(int h, int w) { return h * w; }

auto a = area(10'000'000, 100'000'000);   // bad
Exception(例外)

Use unsigned types if you really want modulo arithmetic.

如果你确实需要按模运算可以使用无符号类型。

Alternative: For critical applications that can afford some overhead, use a range-checked integer and/or floating-point type.

可选项:对于可以承受一定额外开销的敏感应用,使用带有范围检查的整数或者浮点数。

Enforcement(实施建议)

原文链接

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#es103-dont-overflow

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