double c = ldexp(3, 2); // Sets c to 12 = 3 * 2 ^ 2 double d = ldexp(2, 4); // Sets d to 32 = 2 * 2 ^ 4
计算x乘以2的exp次幂 ( x * ( 2^exp ) )
ldexp(x, exp)
x double, float or int
exp double, float or int
返回 double