/***************************************************
Name: check_parity.c
Copyright: kernelxu,Mike Wahler,Joe Wright
Author: kernelxu
Date: 29-08-05 12:10
Description: parity check of an unsigned integer
Compiler: WIN2000+DEV-C++4.9.9.2
My E_mail: kernelxu@hotmail.com
source: http://groups.google.com/group/comp.lang.c/
browse_thread/thread/25bc2430a2ca06f5/
295c349ec797b3c0?hl=en#295c349ec797b3c0
****************************************************/
#include <limits.h>
#include <stdio.h> unsigned int bits1(unsigned int value);
unsigned int bits2(unsigned int value);
unsigned int even(unsigned int value);
unsigned int odd(unsigned int value);
unsigned int odd_even(unsigned value); int main(void)
{
const char *parity[] = {"ODD", "EVEN"}; /*excellent!*/
unsigned int i = 0; puts("Value Bits Parity");
for(; i < 20; ++i)
printf("%5u %4u %s\n", i, bits1(i), parity[even(i)]);
system("pause");
return 0;
}
unsigned int bits1(unsigned int value)
{
unsigned int n = 0;
while (value)
{
value &= (value - 1); /*more efficient than bits2()*/ /* less loops*/
++n;
} return n;
} unsigned int bits2(unsigned int value)
{
unsigned int result = 0;
unsigned int mask = 1; while(mask)
{
result += (value & mask) != 0; /*count the number of '1'*/
mask *= 2; /*equal to "mask <<= 1;"*/
} return result;
}
unsigned int even(unsigned int value)
{
return !(bits1(value) % 2);
} unsigned int odd(unsigned int value)
{
return !even(value); } unsigned int odd_even(unsigned value)
{
return !(0x01 & value); /*return 0 value is odd; */ /*return 1 value is even*/
}
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