【设计型】第11章：指针和数组 子网掩码

<span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码是用来判断任意两台计算机的IP地址是否属于同一子网络的根据。</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">最为简单的理解就是两台计算机各自的IP地址与子网掩码进行AND运算后，如果得出的结果是相同的，则说明这两台计算机是处于同一个子网络上的，可以进行直接的通讯。就这么简单。</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">请看以下示例：</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">运算演示之一：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">IP地址　 &nbsp; 192.168.0.1&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码　 255.255.255.0&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">转化为二进制进行运算：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">IP地址　 &nbsp;11010000.10101000.00000000.00000001&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码　11111111.11111111.11111111.00000000&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">AND运算：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">　　　　　11010000.10101000.00000000.00000000&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">转化为十进制后为：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">　　　　　　192.168.0.0</span><br /> <br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">运算演示之二：&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">IP地址　 &nbsp; 192.168.0.254&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码　 255.255.255.0&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">转化为二进制进行运算：&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">IP地址　 &nbsp;11010000.10101000.00000000.11111110&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码　11111111.11111111.11111111.00000000&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">AND运算：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">　　　　　11010000.10101000.00000000.00000000&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">转化为十进制后为：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">　　　　　　192.168.0.0</span><br /> <br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">运算演示之三：&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">IP地址　 &nbsp; 192.168.0.4&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码　 255.255.255.0</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">转化为二进制进行运算：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">IP地址　 &nbsp;11010000.10101000.00000000.00000100&nbsp;</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">子网掩码　11111111.11111111.11111111.00000000&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">AND运算：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">　　　　　11010000.10101000.00000000.00000000&nbsp;</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">转化为十进制后为：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">　　　　　　192.168.0.0</span><br /> <br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">通过以上对三组计算机IP地址与子网掩码的AND运算后，我们可以看到它运算结果是一样的，均为192.168.0.0，所以计算机就会把这三台计算机视为在同一子网络。</span>

<span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">输入的第一行是本机IP地址；</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">第二行是子网掩码；</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">第三行是一个整数N，表示后面有N个IP地址；</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">接下来N行：</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">第1个IP地址</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">...</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">...</span><br /> <span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">第N个IP地址</span>

<span style="font-family:'Microsoft Yahei';font-size:14px;line-height:28px;background-color:#F5F5F5;">计算并输出N个IP地址是否与本机在同一子网内。对于在同一子网的输出“INNER”，对于在不同子网的输出“OUTER”。</span>