Thread: Set of questions.

Ok Heres another question:
"Write a function, unsigned char exchange(unsigned char in),
which exchanges the right 4 bits of an unsigned char with its left 4 bits (e.g. exchange(0x54) will return 0x45.)"

What would be the logic of the question. I mean for this I want to know what is unsigned char. What would be the value of unsigned char. If that is know I know how to use bit operations.

Originally Posted by Ron

Ok Heres another question:
"Write a function, unsigned char exchange(unsigned char in),
which exchanges the right 4 bits of an unsigned char with its left 4 bits (e.g. exchange(0x54) will return 0x45.)"

What would be the logic of the question. I mean for this I want to know what is unsigned char. What would be the value of unsigned char. If that is know I know how to use bit operations.

unsigned char should be 8 bits

So u mean to say if unsigned char value is 00000045, it should be swapped as 45000000. Is this what the question is asking?

Originally Posted by Ron

So u mean to say if unsigned char value is 00000045, it should be swapped as 45000000. Is this what the question is asking?

No, the question is saying that if the unsigned char is 01000101, it should become 01010100. Eight bits, which you are swapping four-for-four (not reversing two-at-a-time, as you seem to have done).

It may be worth noting that 0x00 indicates that the number is in hexadecimal format.

0x45 is 1 byte or 8 bits. The 4 is 4 bits and the 5 is 4 bits.

0x4 = 0100
0x5 = 0101

0x45 = 01000101

Originally Posted by Ron

so by just doing x=y<<2^2

Do you mean y << 4 here? (Since y << 2^2 is something rather different.) Yes, that would only shift, but you need to swap.

Hmmmm
so can I do this.... x=y<<4
z=y>>4;
y=x+z;
its very amateurish.....

Also, how do I arrange words in ascending order in an array without having to compare each character?

Originally Posted by Ron

Hmmmm
so can I do this.... x=y<<4
z=y>>4;
y=x+z;
its very amateurish.....

That's the easy way to do it.

Originally Posted by Ron

Also, how do I arrange words in ascending order in an array without having to compare each character?

Stop comparing when you find that the two words are different.

Did not understand, I am comparing a list of different words and arranging them in ascending order. How can I do this without comparing each character?

Originally Posted by Ron

Did not understand, I am comparing a list of different words and arranging them in ascending order. How can I do this without comparing each character?

You don't need to compare every character:

adam == eve ?
a == e ? no! done!

How will that put the words in ascending order? Im sure strcmp does not have > or < .

Originally Posted by Ron

How will that put the words in ascending order? Im sure strcmp does not have > or < .

Maybe you should look at what strcmp does then.

Ooops

How can I create a circular array , push the new strings from rear and pop the first strings?

eg: char *s[10]; Like a queue, but with no nodes?