Scala - right shift assignment operator
The Bitwise right shift assignment operator (>>=) assigns the first operand a value equal to the result of Bitwise right shift operation of two operands.
(x >>= y) is equivalent to (x = x >> y)
The Bitwise right shift operator (>>) takes the two numbers and right shift the bits of first operand by number of place specified by second operand. For example: for right shifting the bits of x by y places, the expression (x>>y) can be used. It is equivalent to dividing x by 2y.
The example below describes how right shift operator works:
1000 >> 2 returns 250 (In Binary) 1000 -> 1111101000 >> 2 | right shift the bits ----- V by 2 places 250 <- 11111010 (In Binary)
The code of using right shift operator (>>) is given below:
object MainObject { def main(args: Array[String]) { var x = 1000 //right shift assignment operation x >>= 2 //Displaying the result println("x = " + x) } }
The output of the above code will be:
x = 250
Example: Find largest power of 2 less than or equal to given number
Consider an integer 1000. In the bit-wise format, it can be written as 1111101000. However, all bits are not written here. A complete representation will be 32 bit representation as given below:
00000000000000000000001111101000
Performing
00000000000000000000001111111111
Adding one to this result and then right shifting the result by one place will give largest power of 2 less than or equal to 1000.
00000000000000000000001000000000
The below code will calculate the largest power of 2 less than or equal to given number.
object MainObject { def MaxPowerOfTwo(N: Int) : Int = { var n = N //changing all right side bits to 1. n = n | (n>>1) n = n | (n>>2) n = n | (n>>4) n = n | (n>>8) n = n | (n>>16) //adding 1 to n makes smallest power //of 2 greater than given number n = n + 1 //right shift by one position makes //largest power of 2 less than or //equal to given number n >>= 1 return n } def main(args: Array[String]) { println(s"MaxPowerOfTwo(100) = ${MaxPowerOfTwo(100)}") println(s"MaxPowerOfTwo(500) = ${MaxPowerOfTwo(500)}") println(s"MaxPowerOfTwo(1000) = ${MaxPowerOfTwo(1000)}") } }
The above code will give the following output:
MaxPowerOfTwo(100) = 64 MaxPowerOfTwo(500) = 256 MaxPowerOfTwo(1000) = 512
❮ Scala - Operators