用C铸造双打为整数时溢出的处理 [英] Handling overflow when casting doubles to integers in C

问题描述

今天，我注意到，当我投了两倍，比最大可能的整数到整数时，我得到-2147483648。同样，当我投了两倍，小于最小可能的整数，我也得到-2147483648。

Today, I noticed that when I cast a double that is greater than the maximum possible integer to an integer, I get -2147483648. Similarly, when I cast a double that is less than the minimum possible integer, I also get -2147483648.

这是行为的所有平台定义？

什么是检测这种下溢/溢出的最好方法？如果最小和最大INT报表是放投之前的最佳解决方案？

Is this behavior defined for all platforms?
What is the best way to detect this under/overflow? Is putting if statements for min and max int before the cast the best solution?

推荐答案

limits.h中有最大的常量和最小可能值整数数据类型，您可以检查您铸造，像以前一样的双可变

limits.h has constants for max and min possible values for integer data types, you can check your double variable before casting, like

if (my_double > nextafter(INT_MAX, 0) || my_double < nextafter(INT_MIN, 0))
    printf("Overflow!");
else
    my_int = (int)my_double;

编辑：函数nextafter（）将解决由nwellnhof

nextafter() will solve the problem mentioned by nwellnhof

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