//求一个数的绝对值
#include <stdio.h>
int absolute_value(int num)
{
if (num < 0)
{
num = ~(num - 1);
}
return num;
}
int main()
{
printf("%d\n", absolute_value(5));
printf("%d\n", absolute_value(-5));
printf("%d\n", absolute_value(0));
return 0;
}原文：http://www.cnblogs.com/wgwyanfs/p/6782355.html