Please read about the proper way to post code. The operators you show are binary shift operators. In the first line the binary value, 512, is being shifted left one bit. This results in a value of 1024. In the second line, the value of n (now 1024) is being shifted right one bit. This results in the original value, 512. The third line is merely shorthand for "m = m >> 1;", which results in the value 256.
In a left shift, the rightmost bit becomes a 0. In a right shift, the leftmost bit becomes a zero for unsigned variables, or a duplicate of its previous (before the shift) value for signed variables.