题解 | #识别有效的IP地址和掩码并进行分类统计#

#include <stdio.h>
#include <string.h>
typedef  struct ip {
    int a;
    int b;
    int c;
    int d;
    int e;
    int err;
    int private;
} ips;
ips ipMy = {0, 0, 0, 0, 0, 0, 0};
void islegal(char* table, ips* ipssIndex);
int main() {
    char table[1000][60];
    int tableCnt = 0;
    while (scanf("%s", table[tableCnt]) != EOF) {
        islegal(table[tableCnt], &ipMy);
        tableCnt++;
    }
    printf("%d %d %d %d %d %d %d", ipMy.a, ipMy.b, ipMy.c, ipMy.d, ipMy.e, ipMy.err,
           ipMy.private);
    return 0;
}

void islegal(char* table, ips* ipsIndex) {
    char tableIp[30], tableMask[30];
    char* p = strchr(table, '~');
    *p = 0;
    strcpy(tableIp, table);
    strcpy(tableMask, p + 1);

    int ip1 = 0, ip2 = 0, ip3 = 0, ip4 = 0;
    if(sscanf(tableIp, "%d.%d.%d.%d", &ip1, &ip2, &ip3, &ip4)!=4) {
        ipsIndex->err++;
        return;
    }  //啥也不是

    if (ip1 == 0 || ip1 == 127) return ; //啥也不是
    if (ip1 > 255 || ip2 > 255 || ip3 > 255 || ip4 > 255) { //非法IP
        ipsIndex->err++;
        return;
    }
    /**判断子网掩码*/
    int mask1 = 0, mask2 = 0, mask3 = 0, mask4 = 0;
    if(sscanf(tableMask, "%u.%d.%d.%d", &mask1, &mask2, &mask3, &mask4)!=4){
        ipsIndex->err++;
        return;
    };
    unsigned int mask = \
    ((unsigned int)mask1)<<24|((unsigned int)mask2)<<16|((unsigned int)mask3)<<8|((unsigned int)mask4);
     int flag = 0;
     if(mask==0||mask==0xFFFFFFFF) {
        ipsIndex->err++;
        return;
     }
    for(int i=0;i<32;i++){
        if(((mask<<i)&0X80000000) == 0X80000000) {  //掩码错误
            if(flag) {
                ipsIndex->err++;
                return;
            }
        } else {
            flag = 1;
        }
    }
   /**判断ip类型*/
    if(ip1 >= 1 && ip1 <= 126) { //a
        ipsIndex->a++;
    }else if (ip1 >= 128 && ip1 <= 191) {
        ipsIndex->b++;
    }else if (ip1 >= 192 && ip1 <= 223) {
        ipsIndex->c++;
    }else if (ip1 >= 224 && ip1 <= 239) {
        ipsIndex->d++;
    }else if (ip1 >= 240 && ip1 <= 255) {
        ipsIndex->e++;
    }
    /*判断私有的IP*/
    if (ip1 == 10) ipsIndex->private++;
    if(ip1==172&&ip2>=16&&ip2<=32) ipsIndex->private++;
    if(ip1==192&&ip2==168) ipsIndex->private++;
}