classful addressing

00000000 - 01111111 = class A = 1.xxx.xxx.xxx - 126.xxx.xxx.xxx
10000000 - 10111111 = class B = 128.xxx.xxx.xxx - 191.255.xxx.xxx
11000000 - 11011111 = class C = 192.xxx.xxx.xxx - 223.255.255.xxx
11100000 - 11101111 = class D = 224.xxx.xxx.xxx - 239.x.x.x
11110000 = 11110111 = class E = 240.xxx.xxx.xxx - 247.x.x.x