以下是url中可能用到的特殊字符及在url中的经过编码后的值：

特殊字符的含义

URL编码

#           用来标志特定的文档位置   %23

%         对特殊字符进行编码            %25

&         分隔不同的变量值对             %26

+         在变量值中表示空格             %2B

/          表示目录路径                          %2F

\          表示目录路径                          %5C

=         用来连接键和值                      %3D

?         表示查询字符串的开始          %3F

空格    空格                                         %20

.          句号                                          %2E

:         冒号                                           %3A

参考代码如下：

#include<iostream>
using namespace std;char dec2hexChar(short int n) {if ( 0 <= n && n <= 9 ) {return char( short('0') + n );} else if ( 10 <= n && n <= 15 ) {return char( short('A') + n - 10 );} else {return char(0);}
}short int hexChar2dec(char c) {if ( '0'<=c && c<='9' ) {return short(c-'0');} else if ( 'a'<=c && c<='f' ) {return ( short(c-'a') + 10 );} else if ( 'A'<=c && c<='F' ) {return ( short(c-'A') + 10 );} else {return -1;}
}string escapeURL(const string &URL)
{string result = "";for ( unsigned int i=0; i<URL.size(); i++ ) {char c = URL[i];if (( '0'<=c && c<='9' ) ||( 'a'<=c && c<='z' ) ||( 'A'<=c && c<='Z' ) ||c=='/' || c=='.') {result += c;} else {int j = (short int)c;if ( j < 0 ) {j += 256;}int i1, i0;i1 = j / 16;i0 = j - i1*16;result += '%';result += dec2hexChar(i1);result += dec2hexChar(i0);}}return result;
}string deescapeURL(const string &URL) {string result = "";for ( unsigned int i=0; i<URL.size(); i++ ) {char c = URL[i];if ( c != '%' ) {result += c;} else {char c1 = URL[++i];char c0 = URL[++i];int num = 0;num += hexChar2dec(c1) * 16 + hexChar2dec(c0);result += char(num);}}return result;
}int main()
{string str = "你好 世界";string temp = escapeURL(str);cout<<temp<<endl;cout<<deescapeURL(temp)<<endl;getchar();return 0;
}

结果：

代码自：http://blog.chinaunix.net/uid-20435679-id-1680210.html

相关：

一个URL编码和解码的C++类