^(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9])\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[1-9]|0)\.(25[0-5]|2[0-4][0-9]|[0-1]{1}[0-9]{2}|[1-9]{1}[0-9]{1}|[0-9])$
----------------------------------------
To teach a fish how to swim.
----------------------------------------
To teach a fish how to swim.
private bool Check(string s)
{
if(s.Length>15 || s.Length<7 ) return false; int t=0;
for(int i=0;i<s.Length;i++)
{
if((s[i]<'0' || s[i]>'9') && s[i]!='.') return false;
if(s[i]=='.') t++;
}
if(t!=3) return false;
int f=-1;
for(int i=0;i<s.Length;i++)
{
if(s[i]=='.')
{
if(i-f>4 || i-f<2) return false;
f=i;
}
}
return true;
}
----------------------------------------
To teach a fish how to swim.
if( ( mask + 1 ) & mask )
//掩码不对
if(!((mask & ip ) && ((( mask & ip)+1)&mask)))
//ip与掩码关系不对可是吐学整理的,根据tcp/ip原理而且久经考验的。
ArgumentNullException ipString 为空。
FormatException ipString 不是有效的 IP 地址。 ----------------------------------------
To teach a fish how to swim.