In union members share memory and the memory allocated is equal to the memory allocation of data member which occupies maximum space.
In structure data members do not share memory they have their own memory and are contiguously stored.The memory allocated is equal to the sum of byte allocation of individual members.
+ point:We can access any member at any given time without data corruption.
-point:Squeezes more memory space.
+ point:Occupies less memory.
- point:We can access only one union member at a time without data loss,since the members share memory.