@songpfei
2016-04-06T15:24:52.000000Z
字数 3754
阅读 1992
OJ_算法
请解析IP地址和对应的掩码，进行分类识别。要求按照A/B/C/D/E类地址归类，不合法的地址和掩码单独归类。
所有的IP地址划分为 A,B,C,D,E五类
A类地址1.0.0.0~126.255.255.255;
B类地址128.0.0.0~191.255.255.255;
C类地址192.0.0.0~223.255.255.255;
D类地址224.0.0.0~239.255.255.255；
E类地址240.0.0.0~255.255.255.255
私网IP范围是：
10.0.0.0～10.255.255.255
172.16.0.0～172.31.255.255
192.168.0.0～192.168.255.255
子网掩码为前面是连续的1，然后全是0
多行字符串。每行一个IP地址和掩码，已~隔开。如：
10.70.44.68~255.254.255.0
1.0.0.1~255.0.0.0
192.168.0.2~255.255.255.0
19..0.~255.255.255.0
统计A、B、C、D、E、错误IP地址或错误掩码、私有IP的个数，之间以空格隔开，根据上面的IP，可以得到：
1.0.0.1~255.0.0.0 ----A类
192.168.0.2~255.255.255.0 ----C类，私有
10.70.44.68~255.254.255.0----错误的掩码
19..0.~255.255.255.0-----错误的IP
可以得到统计数据如下：
1 0 1 0 0 2 1
//// huawei_test.cpp : 定义控制台应用程序的入口点。////#include<stdio.h>#include<string.h>#include<stdlib.h>#define N 50int ConvertSubIPToInt(const char* sub_ip){if (sub_ip == NULL)return -1;int length = strlen(sub_ip);if (length < 1 || length>3)return -1;int sub_value = 0;for (int i = 0; i < length; i++){if (sub_ip[i]<'0' || sub_ip[i]>'9')return -1;sub_value = 10 * sub_value + sub_ip[i] - '0';}return sub_value;}bool isIPAddressValid(const char* pszIPAddr, int *subIPValue){// 请在此处实现if (pszIPAddr == NULL || *pszIPAddr == '\0')return false;int szIPAddr_length = strlen(pszIPAddr);int index_start = 0;int index_end = szIPAddr_length - 1;//去除前边的空格while (pszIPAddr[index_start] == ' '){++index_start;}//去除后边空格while (pszIPAddr[index_end] == ' '){--index_end;}if (index_end <= index_start)return false;int ip_length = index_end - index_start + 2;char *temp_ip=(char*)malloc(ip_length);strncpy(temp_ip, pszIPAddr + index_start, ip_length-1);temp_ip[ip_length - 1] = '\0';char* sub_ip = strtok(temp_ip, ".");int sub_ip_count = 0;while (sub_ip != NULL)//ip分段，计数分段ip,并转换为0-255{sub_ip_count++;if (sub_ip_count > 4){free(temp_ip);return false;}subIPValue[sub_ip_count - 1] = ConvertSubIPToInt(sub_ip);if (subIPValue[sub_ip_count - 1] < 0 || subIPValue[sub_ip_count - 1] > 255){free(temp_ip);return false;}sub_ip = strtok(NULL, ".");}free(temp_ip);if (sub_ip_count != 4)return false;elsereturn true;}bool isValidMask(int* mask_value){unsigned int mask_int32 = 0;for (int i = 0; i < 4; i++){mask_int32 += ((unsigned int)mask_value[i]) << ((3 - i) * 8);}mask_int32 = ~mask_int32 + 1;if ((mask_int32 & (mask_int32 - 1)) == 0)//判断是否W为2^n次方return true;elsereturn false;}bool isPrivateIP(int*ip_value){if (ip_value[0] == 10)return true;if (ip_value[0] == 172 && ip_value[1] >= 16 && ip_value[1] <= 31)return true;if (ip_value[0] == 192 && ip_value[1] == 168)return true;return false;}bool IPAnalyse(char* str, int* result){if (str == NULL)return false;char* p = strchr(str, '~');if (p == NULL)return false;else*p = '\0';char* ip = str;char* mask = p + 1;int sub_IP_value[4];int sub_mask_value[4];if (!isIPAddressValid(ip, sub_IP_value) || !isIPAddressValid(mask, sub_mask_value)){result[5]++;return true;//ip无效}if (!isValidMask(sub_mask_value)){result[5]++;return true;//子掩码无效}if (isPrivateIP(sub_IP_value))result[6]++;if (sub_IP_value[0] >= 1 && sub_IP_value[0] <= 126)//A类{result[0]++;return true;}if (sub_IP_value[0] >= 128 && sub_IP_value[0] <= 191)//B类{result[1]++;return true;}if (sub_IP_value[0] >= 192 && sub_IP_value[0] <= 223)//C类{result[2]++;return true;}if (sub_IP_value[0] >= 224 && sub_IP_value[0] <= 239)//D类{result[3]++;return true;}if (sub_IP_value[0] >= 240)//E类{result[4]++;return true;}return false;}int main(){char str[N];int statistic_info[7] = { 0 };while (fgets(str, sizeof(str), stdin) != NULL){if (strlen(str) < 2)break;char* p = strrchr(str, '\n');if (p != NULL)*p = '\0';IPAnalyse(str, statistic_info);}for (size_t i = 0; i < 7; i++){printf("%d ", statistic_info[i]);}return 0;}
int IsSubnetMask(char* subnet){if(if_a_string_is_a_valid_ipv4_address (subnet)){unsigned int b = 0, i, n[4];sscanf(subnet, "%u.%u.%u.%u", &n[3], &n[2], &n[1], &n[0]);for(i = 0; i < 4; ++i) //将子网掩码存入32位无符号整型b += n[i] << (i * 8);b = ~b + 1;if((b & (b - 1)) == 0) //判断是否为2^nreturn 1;}return 0;