1，判断奇偶

for i := 0; i < 100; i++ {
if i % 2 == 0 {
    println(i)
}
if i & 0x1 == 0 {
    println(i)
}

}

2,交换两个数

func Swap(a,b *int) {
	if *a^*b != 0 {
		temp := *a
		*a = *b
		*b = temp
	}
}

func Swap(a,b *int) {
	if *a^*b != 0 {
		*a = *a + *b
		*b = *a - *b
		*a = *a - *b
	}
}

func Swap(a,b *int) {
	if *a^*b != 0 {
		*a ^= *b
		*b ^= *a
		*a ^= *b
	}
}

3，交换符号

func ExcangeSymbol(a int) (ret int) {
	ret = ^a + 1
	return
}

4，求绝对值

func CalcAbs(a int) (ret int) {
    ret = (a ^ a>>31) - a>>31
    return
}

5，二进制逆序

func ByteReverse(a int) int {
    a = ((a & 0xAAAA) >> 1) | ((a & 0x5555) << 1)
    a = ((a & 0xCCCC) >> 2) | ((a & 0x3333) << 2)
    a = ((a & 0xF0F0) >> 4) | ((a & 0x0F0F) << 4)
    a = ((a & 0xFF00) >> 8) | ((a & 0x00FF) << 8)
    return a
}

6，求1的个数

func CalcOneNum(a int) int {
    a = ((a & 0xAAAA) >> 1) + (a & 0x5555)
    a = ((a & 0xCCCC) >> 2) + (a & 0x3333)
    a = ((a & 0xF0F0) >> 4) + (a & 0x0F0F)
    a = ((a & 0xFF00) >> 8) + (a & 0x00FF)
    return a
}