C++ 字符串操作学习

为什么std::string 连最常用，最基本的功能也没有呢？简直是让人无语！

标准C++ 字符串处理增强函数：

//标准C++ string 去除首尾空白字符 2012-8-12 By Dewei
static inline void stringTrim(string &str)
{
	//去除左侧空白符  
	for (std::string::iterator iter = str.begin(); iter != str.end(); ++iter) {   
		if (!isspace(static_cast<unsigned char>(*iter))) {  
			str.erase(str.begin(), iter);  
			break;  
		}  
	}  
	//去除右侧空白符  
	for (std::string::reverse_iterator rev_iter = str.rbegin(); rev_iter != str.rend(); ++rev_iter) {   
		if (!isspace(static_cast<unsigned char>(*rev_iter))) {  
			str.erase(rev_iter.base(), str.end());
			break;  
		}  
	}  
}

//用分隔符将数组合并为字符串 2012-8-12 by Dewei 
//用法：typedef vector<string> stringArray;
string implode(string delimter, stringArray& str_array)
{
	string str;
	int num_count = str_array.size();
	for (int i = 0; i < num_count; ++i) {
		if (!str_array[i].empty())
			str.append(str_array[i]);
		if (i < num_count -1)
			str.append(delimter);
	}
	return str;
}
//将字符串转换成数组(支持值为空) 2012-8-12 by Dewei 
//用法：typedef vector<string> stringArray;
void explode(const std::string &delimter, const std::string &str_source, stringArray *str_array)  
{  
	str_array->clear();  
	if (str_source.empty())  
		return;  
	std::string::size_type num_pos = 0, num_last_pos = 0;  
	num_pos = str_source.find(delimter);
	//num_pos != num_last_pos防止delimter为空字符时死循环
	while (std::string::npos != num_pos && num_pos != num_last_pos) {  
		str_array->push_back(str_source.substr(num_last_pos, num_pos - num_last_pos));
		num_last_pos = num_pos + delimter.length();  
		num_pos = str_source.find(delimter, num_last_pos);
	} 
	str_array->push_back(str_source.substr(num_last_pos)); 
}

//标准C++ std::string 仿CString 替换字符串 by Dewei 2012-6-24
//用法：using namespace std;
//source_str = str_replace(oldstr, newstr, source_str);
static inline string str_replace(const string oldstr, const string newstr, string source_str)
{
	string::size_type num_pos = 0;
	num_pos = source_str.find(oldstr);
	while (num_pos != string::npos) {
		source_str.replace(num_pos, oldstr.length(), newstr);
		num_pos = source_str.find(oldstr, num_pos+oldstr.length());
	}
	return source_str;
}

 

 

 

截取指定区域内字符串：

//CString 截取指字区域内字符串 2012-6-6 By Dewei
//CString strSrc(_T("http://download.youkuaiyun.com/download/lindao0/242800"));
//CString strNew;	
//strNew = substr(strSrc, "//", "/");
//

CString substr(CString strSrc, const CString strStart, const CString strEnd)
{
	int iStart = 0, iEnd = 0;
	CString sSub = "";
	iStart = strSrc.Find(strStart) + lstrlen(strStart) ;
	if (iStart != -1) {
		sSub =	strSrc.Mid(iStart);
		iEnd = sSub.Find(strEnd);
		if (iEnd != -1)
		{
			sSub = sSub.Left(iEnd);
		}
	}
	return sSub;
}

//标准C++ 截取指字区域内字符串 2012-6-23 By Dewei
#include <string>
/*
 *功能：截取字符串的指定范围内的子串
 *参数：strSrc源字符串，strStart开始字符，strEnd结束字符，keepStart是否保留开始字符，keepEnd是否保留结束字符
 */
std::string substr(const std::string &strSrc, const std::string &strStart, const std::string &strEnd, bool keepStart = false, bool keepEnd = false)  
{  
	if (strStart.empty() || strEnd.empty()) {
		return strSrc;
	}
	std::string::size_type iStart = 0, iEnd = 0;  
	std::string sSub = "";  
	iStart = strSrc.find(strStart); 
	if (std::string::npos != iStart) {  
		if (keepStart) 
			sSub =  strSrc.substr(iStart);  
		else
			sSub =  strSrc.substr(iStart + strStart.length());  
		
		iEnd = sSub.find(strEnd);  
		if (std::string::npos != iEnd) {  
			if (keepEnd)
				return sSub.substr(0, iEnd + strEnd.length());
			else
				return sSub.substr(0, iEnd);
		}  
	}  
	return sSub;  
}

//标准C++ 无返回值 截取指字区域内字符串 2012-6-23 By Dewei
#include <string>
using std::string;

//string strSrc("http://download.youkuaiyun.com/download/lindao0/242800");
//char out[1024] = {0};	
//substr(strSrc, "//", "/", out);
//printf("%s", out);
void substr(string &strSrc, const string &strStart, const string &strEnd, char *out)
{
	int iStart = 0, iEnd = 0;
	string sSub = "";
	iStart = strSrc.find(strStart) + strStart.size();
	if (iStart != -1) {
		sSub =	strSrc.substr(iStart);
		iEnd = sSub.find(strEnd);
		if (iEnd != -1) {
			sSub = sSub.substr(0, iEnd);
			strcpy(out, sSub.c_str());
		}
	}
}