这是一个类，直接调用就可以了。

H

class common_tool
{
public:
	common_tool(void);
	~common_tool(void);

	
	std::string read_config(const char* filename,const char* parent_start,const char* parent_end,const char* child_start,const char* child_end);
	/*
	判断在一个字符串里面是否存在查找的字符串
	key 查找字符串
	*/
	const bool exist_parent_key(const char* source,const char* key);

	/*
	得到2个字符串中间的值
	*/
	std::string get_value_between(const char* source,const char* keyname_start,const char* keyname_end);
};

CPP

#include <iostream>
#include <fstream>
#include <string>
#include "common_tool.h"
using namespace std;

common_tool::common_tool(void)
{

}


common_tool::~common_tool(void)
{

}

std::string common_tool::read_config(const char* filename,const char* child_end)
{
	string strEmptyString="";
	ifstream file(filename,ios::in);  
    if (!file.is_open())  
    {  
        return strEmptyString;  
    }  
    string line_string="";  
    string document_txt="";  
    int pos=-1;  
	string keyname_parent_start = parent_start; 
	string keyname_parent_end =parent_end;
	string keyname_child_start = child_start;
	string keyname_child_end = child_end;
	string keyvalue = "";
	bool find_parent_start =false;
	bool find_parent_end =false;
	bool find_parent =false;
    while(getline(file,line_string))  
    {
		//find start of parent keyname
		if(false == find_parent)
		{
		    find_parent_start = exist_parent_key(line_string.c_str(),keyname_parent_start.c_str());
   			if(true == find_parent_start)
			{
				find_parent = true;
			}
		}
		// find end of parent keyname
		find_parent_end = exist_parent_key(line_string.c_str(),keyname_parent_end.c_str());
		if(true == find_parent_end)
		{
			find_parent = false;
			break;
		}

		//find keyvalue by keyname what you want in parent keyname.
		if(true == find_parent)
		{
			keyvalue="";
			keyvalue.append(get_value_between(line_string.c_str(),keyname_child_start.c_str(),keyname_child_end.c_str()));
			if(keyvalue.length()>0)
			{
				break;
			}
		}
    }  
    file.close();  
    return keyvalue;  
}

const bool common_tool::exist_parent_key(const char* source,const char* key)
{
	bool rs = false;
	string keyname = key;
	string line = source;

	int pos = 0;
	pos=line.find(key,0);
	if(pos<0)
	{
		rs = false;
	}
	else
	{
		rs = true;
	}
	return rs;
}

std::string common_tool::get_value_between(const char* source,const char* keyname_end)
{
	bool rs = false;
	string str_source = source;
	string keyvalue = "";
	static const char* str_empty_value = "";
	int pos_start = 0;
	int pos_end = 0;
	int len = 0;
	len = str_source.length();
	if(len<=0)
	{
		return str_empty_value;
	}
	pos_start = str_source.find(keyname_start,0);
	pos_end   = str_source.find(keyname_end,0);
	if(pos_start<0 || pos_end <0)
	{
		return str_empty_value; // can not find!
	}
	int pos_keyvalue_start = pos_start + strlen(keyname_start);
	int len_keyvalue = pos_end - pos_keyvalue_start;//len - pos_keyvalue_start - strlen(keyname_end);
	if(len_keyvalue<=0)
	{
		return str_empty_value;
	}
	keyvalue = str_source.substr(pos_keyvalue_start,len_keyvalue);
    return keyvalue;  
}

完。