您可以乘以100，然后舍入为整数。

You can multiply by 100 and then round to an integer. Then put the decimal point after the first 2 digits.

例如：

void round(double x)
{
   double y = 100 * x;
   int rounded = (int)(y + 0.5);
   printf("%lf rounded = %d.%02d\n", x, rounded / 100, rounded % 100);
}