reverse bits
Write an Efficient C Program to Reverse Bits of a Number ??
Given an integer n, write a function that returns count of trailing zeroes in n!. Examples: Input: n = 5 Output: 1 Factorial of 5 is 20 which has one trailing 0. Input: n = 20 Output: 4 Factorial of 20 is 2432902008176640000 which has 4 trailing zeroes. Input: n = 100 Output: 24
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ReplyDeletesome crazy things are happening here...i tried to post my solution two times...both the time the code that got published was completely different from what i wrote.
ReplyDeleteI had to delete the solution therefore...its happening again and again...its not letting me to post the solution...there is some serious bug.
int a=0,b=31;
ReplyDeletewhile(a<b){
if(((n<<a)&1)^((n<<b)&1)){
n^=1<<a;
n^=1<<b;
}
a++;
b--;
}
hmmmmm...finally...the above code is for any 32 bit integer n.
ReplyDeleteI am unsure if i hv to transform 00...010111 to 00....011101 or 111010...00. The above code is for the latter case.
sorry the inner while loop condition is
ReplyDelete((n>>a)&1)^((n>>b)&1))
@jainendra i think you have posted in some different post..kindly check..:)
ReplyDeletethis code is for reversing individual bits of a number.you have to reverse entire number.
ReplyDeleteeg: 00000101 -> 10100000
you can check this code
ReplyDeleteFor 32-bit integers:
x = ((x >> 16) & 0X0000FFFF) | ((x & 0X0000FFFF) << 16);
x = ((x >> 8) & 0X00FF00FF) | ((x & 0X00FF00FF) << 8);
x = ((x >> 4) & 0X0F0F0F0F) | ((x & 0X0F0F0F0F) << 4);
x = ((x >> 2) & 0X33333333) | ((x & 0X33333333) << 2);
x = ((x >> 1) & 0X55555555) | ((x & 0X55555555) << 1);
x is now the binary reversal of its original value.