blocks|key|965621|text|如果需要的话，可以使用inet_ntop()和inet_pton()。不要使用inet_ntoa(),+inet_aton()和类似的代码，因为它们已被弃用并且不支持ipv6。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|965622|这里有一个很好的guide，里面有很多例子。|965623|//+IPv4+demo+of+inet_ntop()+and+inet_pton()

struct+sockaddr_in+sa;
char+str[INET_ADDRSTRLEN];

//+store+this+IP+address+in+sa:
inet_pton(AF_INET,+"192.0.2.33",+&(sa.sin_addr));

//+now+get+it+back+and+print+it
inet_ntop(AF_INET,+&(sa.sin_addr),+str,+INET_ADDRSTRLEN);

printf("%25s\n",+str);+//+prints+"192.0.2.33"|code-block|syntax|javascript|965624|entityMap|0|LINK|mutability|MUTABLE|url|https://beej.us/guide/bgnet/^0|B|B|N|B|13|O|0|8|5|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@$9|12|A|13|1|14]]|E|$]]|$1|H|3|I|5|J|7|15|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|N|$O|$5|P|Q|R|E|$S|T]]]]

Use <code>inet_ntop()</code> and <code>inet_pton()</code> if you need it other way around. Do not use <code>inet_ntoa(), inet_aton()</code> and similar as they are deprecated and don't support ipv6.
Here is a nice <a href="https://beej.us/guide/bgnet/" rel="noreferrer">guide</a> with quite a few examples.
<pre><code>// IPv4 demo of inet_ntop() and inet_pton()

struct sockaddr_in sa;
char str[INET_ADDRSTRLEN];

// store this IP address in sa:
inet_pton(AF_INET, &quot;192.0.2.33&quot;, &amp;(sa.sin_addr));

// now get it back and print it
inet_ntop(AF_INET, &amp;(sa.sin_addr), str, INET_ADDRSTRLEN);

printf(&quot;%s\n&quot;, str); // prints &quot;192.0.2.33&quot;
</code></pre>

blocks|key|965654|text|我不确定我是否正确理解了这个问题。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|965655|不管怎样，你在找这个吗：|965656|std::string+ip+="192.168.1.54";
std::stringstream+s(ip);
int+a,b,c,d;+//to+store+the+4+ints
char+ch;+//to+temporarily+store+the+'.'
s+>>+a+>>+ch+>>+b+>>+ch+>>+c+>>+ch+>>+d;
std::cout+<<+a+<<+"++"+<<+b+<<+"++"+<<+c+<<+"++"<<+d;|code-block|syntax|javascript|965657|Output:|offset|length|965658|192++168++1++54|965659|entityMap|0|LINK|mutability|MUTABLE|url|http://ideone.com/xPi4n^0|0|0|0|0|7|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@$K|10|L|11|1|12]]|A|$]]|$1|M|3|N|5|F|7|13|8|@]|9|@]|A|$G|H]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

I'm not sure if I understood the question properly.

Anyway, are you looking for this:

<pre><code>std::string ip ="192.168.1.54";
std::stringstream s(ip);
int a,b,c,d; //to store the 4 ints
char ch; //to temporarily store the '.'
s &gt;&gt; a &gt;&gt; ch &gt;&gt; b &gt;&gt; ch &gt;&gt; c &gt;&gt; ch &gt;&gt; d;
std::cout &lt;&lt; a &lt;&lt; " " &lt;&lt; b &lt;&lt; " " &lt;&lt; c &lt;&lt; " "&lt;&lt; d;
</code></pre>

<a href="http://ideone.com/xPi4n" rel="noreferrer">Output:</a>

<pre><code>192 168 1 54
</code></pre>

blocks|key|965685|text|要将字符串转换为in，请执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|965686|in_addr+maskAddr;
inet_aton(netMaskStr,+&maskAddr);|code-block|syntax|javascript|965687|要将in_addr转换为字符串，请执行以下操作：|965688|char+saddr[INET_ADDRSTRLEN];
inet_ntop(AF_INET,+&inaddr,+saddr,+INET_ADDRSTRLEN);|965689|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

To convert string to in-addr:

<pre><code>in_addr maskAddr;
inet_aton(netMaskStr, &amp;maskAddr);
</code></pre>

To convert in_addr to string:

<pre><code>char saddr[INET_ADDRSTRLEN];
inet_ntop(AF_INET, &amp;inaddr, saddr, INET_ADDRSTRLEN);
</code></pre>

blocks|key|750220|text|我能够使用以下代码将字符串转换为DWORD：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|750221|char+strAddr[]+=+"127.0.0.1"
DWORD+ip+=+inet_addr(strAddr);+//+ip+contains+16777343+[0x0100007f+in+hex]

struct+in_addr+paddr;
paddr.S_un.S_addr+=+ip;

char+*strAdd2+=+inet_ntoa(paddr);+//+strAdd2+contains+the+same+string+as+strAdd|code-block|syntax|javascript|750222|我在一个旧MFC代码的维护项目中工作，因此转换不推荐使用的函数调用是不适用的。|750223|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

I was able to convert string to DWORD and back with this code:

<pre><code>char strAddr[] = "127.0.0.1"
DWORD ip = inet_addr(strAddr); // ip contains 16777343 [0x0100007f in hex]

struct in_addr paddr;
paddr.S_un.S_addr = ip;

char *strAdd2 = inet_ntoa(paddr); // strAdd2 contains the same string as strAdd
</code></pre>

I am working in a maintenance project of old MFC code, so converting deprecated functions calls is not applicable.

blocks|key|750256|text|此示例说明如何将字符串转换为ip，反之亦然：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|750257|struct+sockaddr_in+sa;
char+ip_saver[INET_ADDRSTRLEN];

//+store+this+IP+address+in+sa:
inet_pton(AF_INET,+"192.0.1.10",+&(sa.sin_addr));

//+now+get+it+back+
sprintf(ip_saver,+"%25s",+sa.sin_addr));

//+prints+"192.0.2.10"
printf("%25s\n",+ip_saver);+|code-block|syntax|javascript|750258|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

This example shows how to convert from string to ip, and viceversa:

<pre><code>struct sockaddr_in sa;
char ip_saver[INET_ADDRSTRLEN];

// store this IP address in sa:
inet_pton(AF_INET, "192.0.1.10", &amp;(sa.sin_addr));

// now get it back 
sprintf(ip_saver, "%s", sa.sin_addr));

// prints "192.0.2.10"
printf("%s\n", ip_saver); 
</code></pre>

blocks|key|750308|text|第三个inet_pton参数是指向in_addr结构的指针。成功执行inet_pton调用后，in_addr结构将填充地址信息。该结构的S_addr字段包含网络字节顺序的IP地址(逆序)。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|750309|Example+:+

#include+<arpa/inet.h>
uint32_t+NodeIpAddress::getIPv4AddressInteger(std::string+IPv4Address)+{
++++int+result;
++++uint32_t+IPv4Identifier+=+0;
++++struct+in_addr+addr;
++++//+store+this+IP+address+in+sa:
++++result+=+inet_pton(AF_INET,+IPv4Address.c_str(),+&(addr));
++++if+(result+==+-1)+{+++++++++
gpLogFile->Write(LOGPREFIX,+LogFile::LOGLEVEL_ERROR,+_T("Failed+to+convert+IP+%25hs+to+IPv4+Address.+Due+to+invalid+family+of+%25d.+WSA+Error+of+%25d"),+IPv4Address.c_str(),+AF_INET,+result);
++++}
++++else+if+(result+==+0)+{
++++++++gpLogFile->Write(LOGPREFIX,+LogFile::LOGLEVEL_ERROR,+_T("Failed+to+convert+IP+%25hs+to+IPv4"),+IPv4Address.c_str());
++++}
++++else+{
++++++++IPv4Identifier+=+ntohl(*((uint32_t+*)&(addr)));
++++}
++++return+IPv4Identifier;
}|code-block|syntax|javascript|750310|entityMap^0|3|9|H|7|Y|9|1B|7|1W|6|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]|$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Y|8|@]|D|@]|E|$]]]|L|$]]

The third <code>inet_pton</code> parameter is a pointer to an <code>in_addr</code> structure. After a successful <code>inet_pton</code> call, the <code>in_addr</code> structure will be populated with the address information. The structure's <code>S_addr</code> field contains the IP address in network byte order (reverse order).

<pre><code>Example : 

#include &lt;arpa/inet.h&gt;
uint32_t NodeIpAddress::getIPv4AddressInteger(std::string IPv4Address) {
 int result;
 uint32_t IPv4Identifier = 0;
 struct in_addr addr;
 // store this IP address in sa:
 result = inet_pton(AF_INET, IPv4Address.c_str(), &amp;(addr));
 if (result == -1) { 
gpLogFile-&gt;Write(LOGPREFIX, LogFile::LOGLEVEL_ERROR, _T("Failed to convert IP %hs to IPv4 Address. Due to invalid family of %d. WSA Error of %d"), IPv4Address.c_str(), AF_INET, result);
 }
 else if (result == 0) {
 gpLogFile-&gt;Write(LOGPREFIX, LogFile::LOGLEVEL_ERROR, _T("Failed to convert IP %hs to IPv4"), IPv4Address.c_str());
 }
 else {
 IPv4Identifier = ntohl(*((uint32_t *)&amp;(addr)));
 }
 return IPv4Identifier;
}
</code></pre>

blocks|key|965867|text|下面是一些简单易用、线程安全的c%2B%2B函数，可以将uint32_t本机字节序转换为字符串，将字符串转换为本机字节序uint32_t：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|965868|#include+<arpa/inet.h>+//+inet_ntop+&+inet_pton
#include+<string.h>+//+strerror_r
#include+<arpa/inet.h>+//+ntohl+&+htonl
using+namespace+std;+//+im+lazy

string+ipv4_int_to_string(uint32_t+in,+bool+*const+success+=+nullptr)
{
++++string+ret(INET_ADDRSTRLEN,+'\0');
++++in+=+htonl(in);
++++const+bool+_success+=+(NULL+!=+inet_ntop(AF_INET,+&in,+&ret[0],+ret.size()));
++++if+(success)
++++{
++++++++*success+=+_success;
++++}
++++if+(_success)
++++{
++++++++ret.pop_back();+//+remove+null-terminator+required+by+inet_ntop
++++}
++++else+if+(!success)
++++{
++++++++char+buf[200]+=+{0};
++++++++strerror_r(errno,+buf,+sizeof(buf));
++++++++throw+std::runtime_error(string("error+converting+ipv4+int+to+string+")+%2B+to_string(errno)+%2B+string(":+")+%2B+string(buf));
++++}
++++return+ret;
}
//+return+is+native-endian
//+when+an+error+occurs:+if+success+ptr+is+given,+it's+set+to+false,+otherwise+a+std::runtime_error+is+thrown.
uint32_t+ipv4_string_to_int(const+string+&in,+bool+*const+success+=+nullptr)
{
++++uint32_t+ret;
++++const+bool+_success+=+(1+==+inet_pton(AF_INET,+in.c_str(),+&ret));
++++ret+=+ntohl(ret);
++++if+(success)
++++{
++++++++*success+=+_success;
++++}
++++else+if+(!_success)
++++{
++++++++char+buf[200]+=+{0};
++++++++strerror_r(errno,+buf,+sizeof(buf));
++++++++throw+std::runtime_error(string("error+converting+ipv4+string+to+int+")+%2B+to_string(errno)+%2B+string(":+")+%2B+string(buf));
++++}
++++return+ret;
}|code-block|syntax|javascript|965869|公平地说，在写这篇文章的时候，它们还没有经过测试。但这些函数正是我在讨论这个线程时所要寻找的。|965870|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

here's easy-to-use, thread-safe c++ functions to convert uint32_t native-endian to string, and string to native-endian uint32_t: 

<pre><code>#include &lt;arpa/inet.h&gt; // inet_ntop &amp; inet_pton
#include &lt;string.h&gt; // strerror_r
#include &lt;arpa/inet.h&gt; // ntohl &amp; htonl
using namespace std; // im lazy

string ipv4_int_to_string(uint32_t in, bool *const success = nullptr)
{
 string ret(INET_ADDRSTRLEN, '\0');
 in = htonl(in);
 const bool _success = (NULL != inet_ntop(AF_INET, &amp;in, &amp;ret[0], ret.size()));
 if (success)
 {
 *success = _success;
 }
 if (_success)
 {
 ret.pop_back(); // remove null-terminator required by inet_ntop
 }
 else if (!success)
 {
 char buf[200] = {0};
 strerror_r(errno, buf, sizeof(buf));
 throw std::runtime_error(string("error converting ipv4 int to string ") + to_string(errno) + string(": ") + string(buf));
 }
 return ret;
}
// return is native-endian
// when an error occurs: if success ptr is given, it's set to false, otherwise a std::runtime_error is thrown.
uint32_t ipv4_string_to_int(const string &amp;in, bool *const success = nullptr)
{
 uint32_t ret;
 const bool _success = (1 == inet_pton(AF_INET, in.c_str(), &amp;ret));
 ret = ntohl(ret);
 if (success)
 {
 *success = _success;
 }
 else if (!_success)
 {
 char buf[200] = {0};
 strerror_r(errno, buf, sizeof(buf));
 throw std::runtime_error(string("error converting ipv4 string to int ") + to_string(errno) + string(": ") + string(buf));
 }
 return ret;
}
</code></pre>

fair warning, as of writing, they're un-tested. but these functions are exactly what i was looking for when i came to this thread.

blocks|key|965893|text|将十六进制IP地址转换为字符串IP|type|unstyled|depth|inlineStyleRanges|entityRanges|data|965894|#include+<iostream>
#include+<sstream>
using+namespace+std;

int+main()
{
++++uint32_t+ip+=+0x0AA40001;
++++string+ip_str="";
++++int+temp+=+0;
++++for+(int+i+=+0;+i+<+8;+i%2B%2B){
++++++++if+(i+%25+2+==+0)
++++++++{
++++++++++++temp+%2B=+ip+&+15;
++++++++++++ip+=+ip+>>+4;
++++++++}
++++++++else
++++++++{
++++++++++++stringstream+ss;
++++++++++++temp+%2B=+(ip+&+15)+*+16;
++++++++++++ip+=+ip+>>+4;
++++++++++++ss+<<+temp;
++++++++++++ip_str+=+ss.str()%2B"."+%2B+ip_str;
++++++++++++temp+=+0;
++++++++}
++++}
++++ip_str.pop_back();
++++cout+<<+ip_str;
}|code-block|syntax|javascript|965895|输出:10.164.0.1|965896|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

Hexadecimal IP Address to String IP

<pre><code>#include &lt;iostream&gt;
#include &lt;sstream&gt;
using namespace std;

int main()
{
 uint32_t ip = 0x0AA40001;
 string ip_str="";
 int temp = 0;
 for (int i = 0; i &lt; 8; i++){
 if (i % 2 == 0)
 {
 temp += ip &amp; 15;
 ip = ip &gt;&gt; 4;
 }
 else
 {
 stringstream ss;
 temp += (ip &amp; 15) * 16;
 ip = ip &gt;&gt; 4;
 ss &lt;&lt; temp;
 ip_str = ss.str()+"." + ip_str;
 temp = 0;
 }
 }
 ip_str.pop_back();
 cout &lt;&lt; ip_str;
}
</code></pre>

Output:10.164.0.1

how can I convert a string ipAddress (struct in_addr) and vice versa?
and how do I turn in unsigned long ipAddress?
thanks

How to convert string to IP address and vice versa

如何转换字符串ipAddress (结构in_addr)，反之亦然？如何提交未签名的long ipAddress？谢谢

问如何将字符串转换为IP地址，反之亦然
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