Question

我想通过键盘使用整数和点手动输入IP地址代码应该自动检查天气，点之间的整数范围从0到255

这是来自互联网的示例代码一切都很完美，但我希望有机会手动输入IP地址，而不是使用预定义的IP地址

  /* Sample code from Techpulp.
    * You are free to use this source code as you wish.
    * However Techpulp provides no warranty that this code works ans claims no       responsibility for any damage.
     * Author: neo@techpulp.com
     * http://www.techpulp.com/
    */
    #include <stdio.h>
    #include <unistd.h>

    int is_valid_ip(const char *ip_str)
    {
unsigned int n1,n2,n3,n4;

if(sscanf(ip_str,"%u.%u.%u.%u", &n1, &n2, &n3, &n4) != 4) return 0;

if((n1 != 0) && (n1 <= 255) && (n2 <= 255) && (n3 <= 255) && (n4 <= 255)) {
    char buf[64];
    sprintf(buf,"%u.%u.%u.%u",n1,n2,n3,n4);
    if(strcmp(buf,ip_str)) return 0;
    return 1;
}
return 0;
    }


    char *test_ips[] = {
"1.1.1.1",
"255.255.255.255",
"0.123.234.12",
"1.255.4.5",
"127.8.190.29",
"3hu23e832j2....wjdnw",
"3a.3b.2d.5t",
"-1.-1.-1.-1",
"1.1.1.1.3",
NULL
     };


    int main(int argc, char *argv[])
    {
int i = 0;

printf("\n------------------------------------------\n");
printf("IP Address Validation\n");
printf("------------------------------------------\n");
while(test_ips[i]) {
    printf("%20s\t%s\n",
        test_ips[i],
        is_valid_ip(test_ips[i])?"VALID ":"INVALID "
         );
    i++;
}
printf("------------------------------------------\n\n");

return 0;
    }

Answer 1

使用scanf或fgets从标准输入/键盘读取值。

Answer 2

E.g

int main(void){
    char input[32];

    printf("input IP Address : ");
    scanf("%s", input);
    printf("%s\t%s\n",
      input,
      is_valid_ip(input)?"VALID ":"INVALID "
    );

    return 0;
}

Answer 3

用scanf替换sscanf。

if(sscanf(ip_str,"%u.%u.%u.%u", &n1, &n2, &n3, &n4) != 4) return 0;

将成为

if(scanf(ip_str,"%u.%u.%u.%u", &n1, &n2, &n3, &n4) != 4) return 0;

或使用你喜欢的任何来自stdin的函数。

从键盘读取ip地址ipv4并使用scanf函数检查其有效性

3 个答案: