can any one give me the meaning of following line
#define COUNT 2000 #define KEY2 0x2F #define KEY1 0xF8
COUNT,KEY2,KEY1 are the name's given which we going to use next in the prog. but what is 2000,0x2F,0xF8 is address i.e memory location or simply just value.
#define COUNT 2000
it mean's when ever the COUNT appears replace it with 2000;
#define val 0x0f
it mean's when ever the val appears goto the memory location 0x0f and pop-up the value
#define COUNT 2000 it mean's when ever the COUNT appears replace it with 2000
Correct!
#define val 0x0f it mean's when ever the val appears goto the memory location 0x0f and pop-up the value
No!! It has exactly the same meaning as in the first example!
It means purely and simply that wherever val appears it will be replaced with 0x0f
eg,
#define val 0x0f int fred; int array[16]; fred = val; // assigns the value 15 to fred array[val] = 3; // assigns the value 3 to array[15] if( fred > val ) // Tests if the value of fred is greater than 15
Remember, 0x0F (hex) is 15 (decimal)