华为OJ： IP地址判断有效性

蔚落 2022-08-19 13:16 180阅读 0赞

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 <td style="margin:0px; padding:0px; word-break:break-all; word-wrap:break-word; text-align:center"> IP地址判断有效性 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</td> 
 <td style="margin:0px; padding:0px; word-break:break-all; word-wrap:break-word"> 答题时间：&nbsp;00&nbsp;小时&nbsp;00&nbsp;分&nbsp;09&nbsp;秒</td> 
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 <td style="margin:0px; padding:6px 3px 3px; word-break:break-all; word-wrap:break-word; border-right-style:solid; border-right-width:1px; border-right-color:rgb(238,238,238); font-size:14px; border-bottom-style:solid; border-bottom-width:1px; border-bottom-color:rgb(238,238,238)"> 描述:&nbsp;</td> 
 <td style="margin:0px; padding:6px 3px 3px; word-break:break-all; word-wrap:break-word; font-size:14px; border-bottom-style:solid; border-bottom-width:1px; border-bottom-color:rgb(238,238,238)"> 题目标题： 
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 <li style="margin:0px; padding:0px"> 判断输入的字符串是不是一个有效的IP地址 </li> 
 </ul> &nbsp; 详细描述： 请实现如下接口 boolisIPAddressValid(constchar*&nbsp;pszIPAddr) 输入：pszIPAddr&nbsp;字符串 输出：true&nbsp;有效的IP地址，false，无效的IP地址 &nbsp; 约束 
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 <li style="margin:0px; padding:0px"> 输入IP为XXX.XXX.XXX.XXX格式 </li> 
 <li style="margin:0px; padding:0px"> 字符串两端含有空格认为是合法IP </li> 
 <li style="margin:0px; padding:0px"> 字符串中间含有空格认为是不合法IP </li> 
 <li style="margin:0px; padding:0px"> 类似于&nbsp;01.1.1.1，&nbsp;1.02.3.4&nbsp;&nbsp;IP子段以0开头为不合法IP </li> 
 <li style="margin:0px; padding:0px"> 子段为单个0&nbsp;认为是合法IP，0.0.0.0也算合法IP </li> 
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bool isIPAddressValid(const char* pszIPAddr)
 {
 // 请在此处实现
 	int len = 0, i = 0, j = 0,k = 0;
 	const char* tempStr = pszIPAddr;
 	int count = 0, n = 0;
 	char potStr[6] = { 0 };
 	
 	if (pszIPAddr == NULL)
 	{
 		return false;
 	}
 
 	len = strlen(pszIPAddr);
 
 	/*去除头部的空格,然后判断是否合法*/
 	for (i = 0; i < len && tempStr[i] == ' '; i++);
 	if (i == len)
 	{
 		return false;
 	}
 
 	/*去除尾部的空格，判断是否合法*/
 	for (j = len - 1; j >= 0 && tempStr[j] == ' '; j--);
 	if (j == 0)
 	{
 		return false;
 	}
 
 	if (i >= j)
 	{
 		return false;
 	}
 
 	/**判断中间是否有有空格*/
 	for (k = i; k < j; k++)
 	{
 		if (tempStr[k] == ' ')
 		{
 			return false;
 		}
 	}
 
 	/*判断点是否出现在第一个字符或者位置是否有错*/
 	for (k = i; k <= j; k++)
 	{
 		if (tempStr[k] == '.')
 		{
 			potStr[count] = k;
 			count++;
 
 			/* 是否点出现在开始或者结尾 */
 			if (k == i || k == j)
 			{
 				return false;
 			}
 
 			/*是否有两个点挨着*/
 			if (k+1 < len && tempStr[k + 1] == '.')
 			{
 				return false;
 			}
 		}
 	}
 
 	/* 看是否是三个点 */
 	if (count != 3)
 	{
 		return false;
 	}
 
 	potStr[count++] = j + 1;
 
 	/*判断各字段是否为0开头*/
 	k = i;
 	while (n < count)
 	{
 		if (tempStr[k] == '0')
 		{
 			if (k + 1 < len && tempStr[k + 1] != '.')
 			{
 				return false;
 			}
 		}
 
 		k = potStr[n] + 1;
 		n++;
 	}
 
 	/*判断各字段是否在0~255之间*/
 	n = 0;
 	int sum = 0;
 	while (n < count)
 	{ 
 		sum = 0;
 		for (k = i; k < potStr[n]; k++)
 		{
 			if (tempStr[k] < '0' || tempStr[k] > '9')
 			{
 				return false;
 			}
 
 			sum = sum * 10 + tempStr[k] - '0';
 		}
 
 		if (sum > 255)
 		{
 			return false;
 		}
 
 		i = potStr[n] + 1;
 		n++;
 	}
 
 return true;
 }

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