如何在JAVA中将两个int合并为一个double？

Question

如果我有:

int a = 123;
int b = 456;

如何得到？:

double c = 123.456;

Answer 1

这个怎么样:

int a = 123; int b = 456;
double c = Double.parseDouble(a + "." + b);

Answer 2

数学解决方案

  int a = 123; 
  int b = 456;

  double c = a + (b == 0 ? 0 : b / Math.pow(10, 1 + (int) Math.log10(b)));

说明:

   1 + (int) Math.log10(b)     // number of digits (3 in case of 123)
   Math.pow(10, 1 + ... )      // 10...0 - 1 with required number of zeroes