比较两个数的大小--不用大于小于if
public class CompareAandB {
public static void main(String[] args) {
System.out.println(compare(3, 5));
System.out.println(compare(1231, 23));
System.out.println(compare(9, 9));
}
public static int compare(int a , int b){
//a>b 则a-b整数，最高位为0 反之最高位为0
return ((a-b)&0x8000)==0?a:b;
}
}
0x8000 in binary is:
1000 0000 0000 0000
0000 0000 0100 0011 1000 0000 0000 0000 -------------------------------- 0000 0000 0000 0000
1000 0000 0100 0011 1000 0000 0000 0000 -------------------------------- 1000 0000 0000 0000
& for bitwise AND. (4 & 2) is zero, (4 & 5) is 4.
A bitwise AND takes two binary representations of equal length and performs the logical AND operation on each pair of corresponding bits. The result in each position is 1 if the first bit is 1 AND the second bit is 1; otherwise, the result is 0. In this, we perform the multiplication of two bits, i.e. 1 × 0 = 0 and 1 × 1 = 1. For example:
0101 (decimal 5) AND 0011 (decimal 3) = 0001 (decimal 1)
