ip地址判断，子网判断，掩码判定

'&&str[1]=='0'&&str[2]!='.') //判断第一个数是否为零开头的，例如 099.111.111.111

{ }

for(i=0;i<16;i++) {

printf(\return 0;

if(str[i]=='.'&&str[i+1]=='0'&&str[i+2]!='.'&&str[i+2]!='\\0'&&str

[i+2]!=' '&&str[i+2]!='/')

{ //1.

避免出现111.011.022.033的子网地址

printf(\

return 0;

} else

if(str[i]=='.'&&str[i+1]=='\\0'||str[i]=='

'&&str[i+1]=='0'&&str[i+2]!='.'||str[i]=='.'&&str[i+1]==' ')

{ //2.

避免最后一个数字是零的情况下以空格结尾判断失误

printf(\避

免最后出现类似 1.1.1.1..地址

return 0; //4.避

免类似\地址

}

printf(\

}

)

} else { }

//判断掩码合法性 q=Mask_judge(a); if(e>=q&&e<=31)

printf(\掩码合法: %d\\n\

printf(\return 0;

else if(e

printf(\掩码非法: %d小于%d\\n\

else

if(o!=1)

//判断ip地址是否正确

printf(\斜杠只能出现一次!\\n\printf(\掩码非法: %d>31\\n\

if((f>=0&&f<=255)&&(g>=0&&g<=255)&&(h>=0&&h<=255)&&(i>=0&&j<=255)

{

if(str[z]=='0'&&str[z+1]!='.'||str[z]=='

'&&str[z+1]=='0'&&str[z+2]!='.') //判断第一个数是否为零开头的，例如 099.111.111.111

{ }

for(i=z;i

printf(\return 0;

if(str[i]=='.'&&str[i+1]=='0'&&str[i+2]!='.'&&str[i+2]!='\\0'&&str

[i+2]!=' ')

{ //1.

避免出现111.011.022.033的错误ip地址

printf(\

return 0;

} else

if(str[i]=='.'&&str[i+1]=='\\0'||str[i]=='

'&&str[i+1]=='0'&&str[i+2]!='.'||str[i]=='.'&&str[i+1]==' ')

{ //2.

避免最后一个数字是零的情况下以空格结尾判断失误

printf(\避

免最后出现类似 1.1.1.1..地址

return 0; //4.避

免类似\地址

}

}

}

printf(\

else { }

//判断ip_add是否属于子网 a2=atoi(itoa(a, str2, 2)); b2=atoi(itoa(b, str2, 2)); c2=atoi(itoa(c, str2, 2)); d2=atoi(itoa(d, str2, 2));

printf(\return 0;

/* printf(\

printf(\printf(\printf(\f2=atoi(itoa(f, str2, 2)); g2=atoi(itoa(g, str2, 2)); h2=atoi(itoa(h, str2, 2)); j2=atoi(itoa(j, str2, 2));

/* printf(\

printf(\printf(\printf(\num=e/8;

mod=8-e%8;

divider=pow(10,mod);

// printf(\

if(num==1&&f2==a2&&g2/divider==b2/divider) { }

printf(\地址属于该子网1!\\n\return 0;

else if(num==2&&f2==a2&&g2==b2&&h2/divider==c2/divider) { }

printf(\地址属于该子网2!\\n\return 0;

else

if(num==3&&f2==a2&&g2==b2&&h2==c2&&j2/divider==d2/divider)

else /*

printf(\

printf(\地址不属于该子网!\\n\

{ }

printf(\地址属于该子网3!\\n\return 0;