Data Type and format specifier

DATA Types
Objective supports all data type which are in c.
Similar to c (bool) Objective C has  extra data type is BOOL used specially in COCOA.
BOOL is typedefed to signed char . which require 8 bit to store. Some time in c non zero value is consider as true so here take care if u are assigning nonzero value say 0x1230 to BOOL it will get last byte which is zero (means False or NO value).
BOOL use YES which is #defined to 1 and NO which is #defined to 0. Take care this condition also when programing comparing YES with non zero number.

Here imp is Non Zero value is not same as YES. (in c non zero is true ).
So to avoid this Its better to compare with NO (zero value) is always safe.

Forma Specifier
Objective c uses the same format specifier as the c .
There is one addition format specifier for displaying object details :- %@
when u pass %@ and object to NSLog  . NSLog calls description() method of that object which returns object details in NSString format.

XCode shortcut:- to run app use ⌘⇧R.

%@	For any object
%%	Writes a % character.
%d,%D	signed 32-bit integer
%u or %U	unsigned 32-bit integer
%x	signed int as a hexadecimal character
%X	unsigned int as a hexadecimal character
%o,%O	an unsigned 32-bit int in octal format.
%f	double value (64-bit floating-point number)
%e	64-bit floating-point double value in  exponent format.
%E	64-bit floating-point double value in uppercase  exponent format.
%g	double (64 bit floating point) in the %e format when the exponent is less than -4 or if greater or equal to the precision as %f.
%G	As the %g format but in uppercase (E).
%c	Output an unsigned char
%C	unsigned 16-bit unichar character.
%s	Outputs an 8 bit null terminated unsigned character.
%S	Unicode null terminted characters.
%p	void* pointer in hexadecimal format
%a	double also known as a 64-bit floating-point number.
%A	as above but the exponential symbol is in uppercase.
%F	double in decimal notation