Where do we use/need union?

Question

Okay, so union is a data type which can store different types of data but only one member can contain a value at a time.

Answer 1

Unions allow quick conversion between data making use of addressable units. Usually, all members contain a single value at the same time.

I've used a compiler where each bit was individually assignable to a field so converting to binary was as simple as put the integer in the union and print out the array of bits from the union.

In compiler writing, it makes putting instructions together simple. You can write the individual bytes to the binary object file. Treat addresses as a multibyte units, etcetera.

However, in the normal day in and day out programming, it doesn't serve a purpose because that type of low level conversion isn't required.

Answer 2

https://www.crazyengineers.com/threads/use-of-unions-in-c.21703/

refer the above link
Union was used in older days when main memory size was small.

Answer 3

Here an useful example to convert color bytes into the integer needed to set a color.
https://code.sololearn.com/cHywd0RPiIP4

Answer 4

John Wells Thank you sir

Answer 5

I'm not familiar with this topics

Answer 6

we need union when we work with same kind of tables...having same column names with same data types.

Answer 7

we need union when we work with recursive query.
example: hierarchical data such country and cities relationship