objective-c - difference between char and unichar?

Question

I searched a lot about the difference of unichar and char but did't get any clear concept. also tell me difference about char[] and unichar[].

when use char and unichar ??

Answer 1

char is 8 bits and represents either an arbitrary 8-bit number, or a UTF-8 code unit, or a code unit in some other character encoding.

unichar is 16 bits and represents a UTF-16 code unit.

Answer 2

unichar is twice the size of char.

unichar often used in other language codes:

difference for example:

char a = 'y'; (correct)
char a = '字'; (wrong)

unichar a = '字'; （correct）

char a[2]  : 8bit * 2

unichar a[2] : 16bit *2

hope it helps.