C++ 将 double 转换为 long

Question

我在程序中使用了pow(double base, double exponent) ，如何将答案转换为long数据类型？

Answer 1

Just use one of the following statements (depending on your personal requirements):

1. lround(pow(base, exp)); (nearest number to the result)
2. floor(pow(base, exp)); (nearest number less than the result)
3. ceil(pow(base, exp)); (nearest number larger than the result)

Answer 2

I was looking for an actual conversion from double to long.

After some research, casting actually does the trick:

double myDouble = 12.345;
long myTruncatedLong = (long) myDouble;

myTruncatedLong will be 12.