查找类、广播和网络地址的程序
先决条件 - 介绍和有类寻址，无类寻址
给定一个字符串形式的有效 IPv4 地址。任务是确定给定 IPv4 地址的类别以及从中分离的网络和主机 ID 部分。
IPv4 地址：
互联网上的每台主机和路由器都有一个 IP 地址，该地址对其网络号和主机号进行编码，两者的组合是唯一的。 IP地址实际上并不是指主机，而是指网络接口，所以如果主机在两个网络上，它必须有两个IP地址。
默认掩码：
地址掩码决定IP地址的哪一部分代表网络号，哪一部分代表主机号，例如IP地址，掩码有四个八位字节。如果掩码的给定位是 1，则 IP 地址的对应位是网络内部分，如果掩码的给定位是 0，则 IP 地址的对应位是主机部分。
CIDR：
无类域间路由使用斜杠 (/) 表示法来指定带有 IPv4 地址的掩码。地址以 xyzt/n 形式给出，其中 xyzt 是 IP 地址，n 是默认掩码中 1 的数量。
网络地址：
网络的第一个地址是网络地址。它是通过将掩码与 IP 地址（均为二进制形式）进行“与”运算而获得的。另一种方法是将 IP 地址的最后 32-n 位设置为 0。
广播地址：
网络的最后一个地址是广播地址。它是通过将补码掩码与 IP 地址（均为二进制形式）进行 OR 运算而获得的。另一种方法是将 IP 地址的最后 32-n 位设置为 1。
班级：
地址的类别由地址的第一个字节标识。目前有A、B、C、D、E五个类，每个类第一个字节的范围是：
Class A: 0 - 127
Class B: 128 - 191
Class C: 192 - 223
Class D: 224 - 239
Class E: 240 - 255 示例 1：
CIDR: 192.168.32.1/24(x.y.z.t/n)
IP Address(Binary): 11000000101010000010000000000001
Default Mask(Binary): 11111111111111111111111100000000
Default Mask: 255.255.255.0
32-n=32-24=8
First Address: Set last 8 bits of IP address to 0
= 11000000101010000010000000000000
= 192.168.32.0
Last Address: Set last 8 bits of IP address to 1
= 11000000101010000010000011111111
= 192.168.32.255 示例 2：
CIDR: 205.15.37.39/28(x.y.z.t/n)
IP Address(Binary): 11001101000011110010010100100111
Default Mask(Binary): 11111111111111111111111111110000
Default Mask: 255.255.255.240
32-n=32-28=4
First Address: Set last 4 bits of IP address to 0
= 11001101000011110010010100100000
= 205.15.37.32
Last Address: Set last 4 bits of IP address to 1
= 11001101000011110010010100101111
= 205.15.37.47 执行：
下面的代码使用了上面提到的概念：
C++
#include
#include
#include
#include
#include
using namespace std;
// Converts IP address to the binary form
vector bina(vector str)
{
vector re(32,0);
int a, b, c, d, i, rem;
a = b = c = d = 1;
stack st;
// Separate each number of the IP address
a = stoi(str[0]);
b = stoi(str[1]);
c = stoi(str[2]);
d = stoi(str[3]);
// convert first number to binary
for (i = 0; i <= 7; i++)
{
rem = a % 2;
st.push(rem);
a = a / 2;
}
// Obtain First octet
for (i = 0; i <= 7; i++) {
re[i] = st.top();
st.pop();
}
// convert second number to binary
for (i = 8; i <= 15; i++) {
rem = b % 2;
st.push(rem);
b = b / 2;
}
// Obtain Second octet
for (i = 8; i <= 15; i++) {
re[i] = st.top();
st.pop();
}
// convert Third number to binary
for (i = 16; i <= 23; i++) {
rem = c % 2;
st.push(rem);
c = c / 2;
}
// Obtain Third octet
for (i = 16; i <= 23; i++) {
re[i] = st.top();
st.pop();
}
// convert fourth number to binary
for (i = 24; i <= 31; i++) {
rem = d % 2;
st.push(rem);
d = d / 2;
}
// Obtain Fourth octet
for (i = 24; i <= 31; i++) {
re[i] = st.top();
st.pop();
}
return (re);
}
// cls returns class of given IP address
char cls(vector str)
{
int a = stoi(str[0]);
if (a >= 0 && a <= 127)
return ('A');
else if (a >= 128 && a <= 191)
return ('B');
else if (a >= 192 && a <= 223)
return ('C');
else if (a >= 224 && a <= 239)
return ('D');
else
return ('E');
}
// Converts IP address
// from binary to decimal form
vector deci(vector bi)
{
vector arr(4,0);
int a, b, c, d, i, j;
a = b = c = d = 0;
j = 7;
for (i = 0; i < 8; i++) {
a = a + (int)(pow(2, j)) * bi[i];
j--;
}
j = 7;
for (i = 8; i < 16; i++) {
b = b + bi[i] * (int)(pow(2, j));
j--;
}
j = 7;
for (i = 16; i < 24; i++) {
c = c + bi[i] * (int)(pow(2, j));
j--;
}
j = 7;
for (i = 24; i < 32; i++) {
d = d + bi[i] * (int)(pow(2, j));
j--;
}
arr[0] = a;
arr[1] = b;
arr[2] = c;
arr[3] = d;
return arr;
}
int main()
{
string ipr = "192.168.1.1/24";
// You can take user input here
// instead of using default address
// Ask user to enter IP address of form(x.y.z.t/n)
cout<<"IP address CIDR format is:"<< ipr;
// Separate IP address and n
string str1 = "";
int idx = 0;
int len = ipr.size();
len -= 3;
while(len--){
str1 += ipr[idx];
idx++;
}
cout< str;
string temp;
int n = tr.size();
for(int i = 0; i < n; i++){
if(tr[i] >= 48 && tr[i] <= 57)
temp +=tr[i];
else{
str.push_back(temp);
temp = "";
}
}
str.push_back(temp);
//cout< b;
cout< ntwk(32,0);
vector brd(32,0);
int t = 32 - n;
// Obtaining network address
for (int i = 0; i <= (31 - t); i++) {
ntwk[i] = b[i];
brd[i] = b[i];
}
// Set 32-n bits to 0
for (int i = 31; i > (31 - t); i--) {
ntwk[i] = 0;
}
// Obtaining Broadcast address
// by setting 32-n bits to 1
for (int i = 31; i > (31 - t); i--) {
brd[i] = 1;
}
cout< nt = deci(ntwk);
// Converting broadcast address to decimal
vector br = deci(brd);
// Printing in dotted decimal format
cout<<"First Address : " << nt[0] << "." < Java
import java.util.*;
import java.io.*;
import java.net.*;
import java.lang.Math;
class Ip {
// Converts IP address to the binary form
public static int[] bina(String[] str)
{
int re[] = new int[32];
int a, b, c, d, i, rem;
a = b = c = d = 1;
Stack st = new Stack();
// Separate each number of the IP address
if (str != null)
{
a = Integer.parseInt(str[0]);
b = Integer.parseInt(str[1]);
c = Integer.parseInt(str[2]);
d = Integer.parseInt(str[3]);
}
// convert first number to binary
for (i = 0; i <= 7; i++)
{
rem = a % 2;
st.push(rem);
a = a / 2;
}
// Obtain First octet
for (i = 0; i <= 7; i++) {
re[i] = st.pop();
}
// convert second number to binary
for (i = 8; i <= 15; i++) {
rem = b % 2;
st.push(rem);
b = b / 2;
}
// Obtain Second octet
for (i = 8; i <= 15; i++) {
re[i] = st.pop();
}
// convert Third number to binary
for (i = 16; i <= 23; i++) {
rem = c % 2;
st.push(rem);
c = c / 2;
}
// Obtain Third octet
for (i = 16; i <= 23; i++) {
re[i] = st.pop();
}
// convert fourth number to binary
for (i = 24; i <= 31; i++) {
rem = d % 2;
st.push(rem);
d = d / 2;
}
// Obtain Fourth octet
for (i = 24; i <= 31; i++) {
re[i] = st.pop();
}
return (re);
}
// cls returns class of given IP address
public static char cls(String[] str)
{
int a = Integer.parseInt(str[0]);
if (a >= 0 && a <= 127)
return ('A');
else if (a >= 128 && a <= 191)
return ('B');
else if (a >= 192 && a <= 223)
return ('C');
else if (a >= 224 && a <= 239)
return ('D');
else
return ('E');
}
// Converts IP address
// from binary to decimal form
public static int[] deci(int[] bi)
{
int[] arr = new int[4];
int a, b, c, d, i, j;
a = b = c = d = 0;
j = 7;
for (i = 0; i < 8; i++) {
a = a + (int)(Math.pow(2, j)) * bi[i];
j--;
}
j = 7;
for (i = 8; i < 16; i++) {
b = b + bi[i] * (int)(Math.pow(2, j));
j--;
}
j = 7;
for (i = 16; i < 24; i++) {
c = c + bi[i] * (int)(Math.pow(2, j));
j--;
}
j = 7;
for (i = 24; i < 32; i++) {
d = d + bi[i] * (int)(Math.pow(2, j));
j--;
}
arr[0] = a;
arr[1] = b;
arr[2] = c;
arr[3] = d;
return arr;
}
public static void main(String args[])
{
int i;
String[] str = new String[4];
String ipr = "192.168.1.1/24";
// You can take user input here
// instead of using default address
// Ask user to enter IP address of form(x.y.z.t/n)
System.out.println("IP address CIDR format is:" + ipr);
// Separate IP address and n
String[] str1 = ipr.split("/");
// IP address
String tr = str1[0];
// Split IP address into 4 subparts x, y, z, t
str = tr.split("\\.");
int[] b = new int[32];
System.out.println();
// Convert IP address to binary form
b = bina(str);
int n = Integer.parseInt(str1[1]);
int[] ntwk = new int[32];
int[] brd = new int[32];
int t = 32 - n;
// Obtaining network address
for (i = 0; i <= (31 - t); i++) {
ntwk[i] = b[i];
brd[i] = b[i];
}
// Set 32-n bits to 0
for (i = 31; i > (31 - t); i--) {
ntwk[i] = 0;
}
// Obtaining Broadcast address
// by setting 32-n bits to 1
for (i = 31; i > (31 - t); i--) {
brd[i] = 1;
}
System.out.println();
// Obtaining class of Address
char c = cls(str);
System.out.println("Class : " + c);
// Converting network address to decimal
int[] nt = deci(ntwk);
// Converting broadcast address to decimal
int[] br = deci(brd);
// Printing in dotted decimal format
System.out.println("Network Address : " + nt[0]
+ "." + nt[1] + "." + nt[2] + "." + nt[3]);
// Printing in dotted decimal format
System.out.println("Broadcast Address : "
+ br[0] + "." + br[1] + "." + br[2] + "." + br[3]);
}
} 输出：
IP address CIDR format is:192.168.1.1/24
Class : C
Network Address : 192.168.1.0
Broadcast Address : 192.168.1.255