字符串是目前处理是目前工程项目中出现最多的问题，尤其是自然语言处理，文本处理和分析等等，c++目前只提供比较简单的字符串处理函数，不像Python，Java对字符串操作功能强大，下面是自己封装的几个常用字符处理的函数，其实功能实现应该有很多种，但是由于字符串处理是基础函数，需要适当的考虑算法实现的性能。下面是自己实现的一些功能，性能感觉还不错。
/*********************************************function: string common functions.author: liuyidate: 2015.08.29vesion: 1.0**********************************************/#ifndef STR_FUN_H#define STR_FUN_H#include <iostream>#include <string.h>#include <string>#include <vector>using namespace std;inline void split_string(const char* src, const string& sep, vector<string>& split_vec){const char *separator = sep.c_str();split_vec.clear();split_vec.reserve(16);if(src == NULL || separator == NULL)return;const char *p = strstr(src, separator);if(NULL == p){split_vec.push_back(src);return;}if(p == src){split_vec.push_back("");}else{split_vec.push_back(string(src, p – src));}size_t len = strlen(separator);const char* pre = p + len;while(p = strstr(p + len, separator)){split_vec.push_back(string(pre, p – pre));pre = p + len;}if('\0' == *pre){split_vec.push_back("");}else{split_vec.push_back(string(pre));}}inline void split_string(const string& src, const string& sep, vector<string>& split_vec){string::size_type i = src.find(sep);if(string::npos == i){split_vec.push_back(src);return;}if(0 == i){split_vec.push_back("");}else{split_vec.push_back(src.substr(0, i));}size_t len = sep.size();string::size_type pre = i + len;while(string::npos != (i = src.find(sep, pre))){split_vec.push_back(src.substr(pre, i – pre));pre = i + len;}split_vec.push_back(src.substr(pre));}inline string join_string(const string& sep, const vector<string>& str_vec){string str;str.reserve(32*str_vec.size());size_t len = str_vec.size();if(len > 0){str = str_vec[0];}for(size_t i = 1; i < len; i++){str.append(sep);str.append(str_vec[i]);}return str;}inline string replace_string(const string& raw_str, const string& src_str, const string& replace_str){string new_str;new_str.reserve(raw_str.size()*2);size_t begin = 0;size_t len = src_str.size();string::size_type i = raw_str.find(src_str);if(string::npos == i)return raw_str;do{new_str.append(raw_str.substr(begin, i – begin));new_str.append(replace_str);begin = i + len;}while(string::npos != (i = raw_str.find(src_str, begin)));return new_str.append(raw_str.substr(begin));}inline string lstrip(const string& src, const string& sub_str){size_t len = sub_str.size();string::size_type i = 0;i = src.find(sub_str, i);int count = 0;if(i == 0){count = 1;while((i = src.find(sub_str, i+len)) != string::npos){if(i != len*count)break;count++;}}else{return src;}return src.substr(len*count);}inline string rstrip(const string& str, const string& sub_str){int sub_len = sub_str.size();int last_index = str.size()-1;for(int i = last_index; i >= 0; i -= sub_len){int flag = 0;for(int j = 0; j < i && j < sub_len; j++){if(sub_str[j] != str[i + 1 – sub_len + j]){flag = 1;break;}}if(flag == 1){break;}else{last_index = i – sub_len;}}return str.substr(0, last_index+1);}inline string strip(const string& src, const string& sub_str){return lstrip(rstrip(src, sub_str), sub_str);}inline int count_of_substr(const string& str, const string& sub_str){int count = 0;size_t len = sub_str.size();string::size_type i = 0;while((i = str.find(sub_str, i))!= string::npos){count++;i += len;}return count;}inline int count_of_substr(const char *src, const string& sub_str){int count = 0;size_t len = sub_str.size();const char *p = sub_str.c_str();const char *index = src;while(NULL != (index = strstr(index, p))){count++;index += len;}return count;}inline string lower_string(const string& src){string lower_str = src;size_t len = src.size();for(size_t i = 0; i < len; i++){if(src[i] >= 'A' && src[i] <= 'Z')lower_str[i] += 32;}return lower_str;}inline string upper_string(const string& src){string upper_str = src;size_t len = src.size();for(size_t i = 0; i < len; i++){if(src[i] >= 'a' && src[i] <= 'z')upper_str[i] -= 32;}return upper_str;}#endif#include <iostream>#include <stdlib.h>#include "str_fun.h"using namespace std;int main(int agrc, char *argv[]){char s[16] = {"12#34#56"};vector<string> v;split_string(string(s), "#", v);for(int i = 0; i < v.size(); i++)cout<<v[i]<<endl;cout<<join_string("#", v)<<endl;cout<<replace_string(s, "34", "")<<endl;cout<<count_of_substr("##", "#")<<endl;cout<<lower_string("AbC")<<endl;cout<<upper_string("AbC")<<endl;cout<<lstrip("aaaabc", "aab")<<endl;cout<<rstrip("abcabcabc", "abcd")<<endl;cout<<strip("abcabcaba", "a")<<endl;}
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用积极的拼搏迎接雨后的彩虹,相信自己
