11111111换算成十进制是多少？

这是几进制？
如果是2进制1*2^0+1*2^1+1*2^2+1*2^3+1*2^4+1*2^5+1*2^6+1*2^7=1+2+4+8+16+32+64+128=255

11,111,111 + 1 = 100,000,000 = 1*2^8 = 256
11111111 = 255

如果不是二进制，是 N 进制，则
11111111 = 1*N^7 + 1*N^6 + 1*N^5 .... + 1*N + 1*N^0 =
(N^8 - 1)/(N-1)

1*2^0+1*2^1+1*2^2+1*2^3+1*2^4+1*2^5+1*2^6+1*2^7=1+2+4+8+16+32+64+128=255

2^7+2^6+2^5+2^4+2^3+2^2+2+1=128+64+32+16+8+4+2+1=255

简单,一直除2