In 1 and "two's complement" modes, the 40th power of 10 is less than the 2nd power of 133, that is, 133 bits or no more than 17 bytes can be stored.

2. Using a relatively wasteful BCD code, the 40th power of 10 has 4 1 bits, 4 bits each, *** 164 bits or less than 2 1 byte.

3. DPD compressed decimal mode, 4 1 bit, every three bits 10, 14 * 10 = 140 bits or no more than 18 bytes.

4. Bytes correspond to decimal, and 4 1 bit is used for 4 1 byte.

"What is the size of a one-dimensional array of length 40?"

This depends on the size of each array element, and the occupied space = (space of each element+extra information of each element) times the extra information of 40+ array.