Total size of this structure will be 12 byte on 32-bit machine. Because first character's size will be only 1 Byte but due to memory alignment( Algorithm to fast access memory by CPU) , 3 byte will as structure Hole. Because next data is integer which size is 4 Byte.
To avoid this user have to write structure very carefully.
Now It's size will be 8 byte. First two character will come to on Four Byte cycle where actually size of these two character is 2 byte. But it is better that 1st structure.
This things happen only due to easily and fast access memory by CPU.