试试这个:

double a;
memcpy(&a, ptr, sizeof(double));

其中 ptr 是指向您的字节数组的指针.如果你想避免复制使用联合，例如

where ptr is the pointer to your byte array. If you want to avoid copying use a union, e.g.

union {
  double d;
  char bytes[sizeof(double)];
} u;
// Store your data in u.bytes
// Use floating point number from u.d