Left shifts the value of a variable by the number of bits specified in the value of an expression and assigns the result to the variable.
result <<= expression
Using the <<= operator is exactly the same as specifying:
result = result << expression
The <<= operator shifts the bits of result left by the number of bits specified in expression. For example:
var temp temp = 14 temp
The variable temp has a value of 56 because 14 (00001110 in binary) shifted left two bits equals 56 (00111000 in binary). Bits are filled in with zeroes when shifting.