Bit masking

[randysimes]

I have a 32bit number (unsigned int), I want to set another 32bit number to only a certain series of bits. For instance:
1000 0000 1011 1010 0111 1001 1101 0011 is what is given.

I want to set another number to bits 3 - 16 from the left, so bits 17 - 30.

I tried newNum = (given & 0x3FFF0000) but it is incorrect.
1000 0000 1011 1010 0111 1001 1101 0011given
0011 1111 1111 1111 0000 0000 0000 0000mask
---------------------------------------------------------------
The correct answer is 0000 0000 1011 1010 0000 0000 0000 0000

What am I doing wrong?

[donbock]

You told us the "correct" answer ... what is the "wrong" answer that prompted you to post this question?

[hype261]

Not the best at Bit masking

I am not the best at bit masking, but I believe you need to do
int newNum = given & 0x00FF0000

[weaknessforcats]

If you have:

1100

(which is 12 decinal) and you want to change it to:

1110

(which is 14 decimal)

you need to set bit 1 (counting from right).

To get a 1 in position 1 you use 1 < 1 which is 0010. Then you OR:

1100
0010
and the OR result is:

1110.

unsigned int data = 12;    //the 1100
data = data | 1 <1;

To turn the bit off you create a mask where the desired bit is off and all the other bits are ON. The mask for 0010 is 1101:

1110
1101
and the AND result is

1100.

data = data & ~(1<1);    // the bitwise not reverses 1's and 0's.

I'm sure this is in a book somewhere (like the C Programming Language).

Do not use this in C++. Use the bitset template instead.