Boolean type

• 'C' language has boolean type which can take values true and false.

• Objective C has similar type BOOL, which can hold values YES and NO.

• BOOL in Objective C is only typedef for signed char.

• Compiler considers BOOL to be 8 bit number.

• Internally manages NO with 0 value and YES with value 1.

• Since this can hold any number. If more than 1 byte long value assigned, such as short and int is assigned, only the lowest byte value is used for BOOL.

• BOOL is not like 'C' where non zero value is considered true.