ifstream讀取unicode文本到string時(shí)，需要過濾文本開始ff fe兩個(gè)字節(jié)，否則轉(zhuǎn)成gbk會(huì)失敗。

ifstream讀取utf8文本到string時(shí)，需要過濾文本開始efbbbf三個(gè)字節(jié)，否則轉(zhuǎn)成gbk會(huì)失敗。

下面是實(shí)現(xiàn)代碼：

#include <iostream>#include <string>#include <fstream>#include <iconv.h>using namespace std;#PRagma comment(lib,"libIconv.lib")//編碼轉(zhuǎn)換，source_charset是源編碼，to_charset是目標(biāo)編碼std::string code_convert(char *source_charset, char *to_charset, const std::string& sourceStr) //sourceStr是源編碼字符串{	iconv_t cd = iconv_open(to_charset, source_charset);//獲取轉(zhuǎn)換句柄，void*類型	if (cd == 0)		return "";    size_t inlen = sourceStr.size();	size_t outlen = 255;	char* inbuf = (char*)sourceStr.c_str();	char outbuf[255];//這里實(shí)在不知道需要多少個(gè)字節(jié)，這是個(gè)問題	//char *outbuf = new char[outlen]; 另外outbuf不能在堆上分配內(nèi)存，否則轉(zhuǎn)換失敗，猜測跟iconv函數(shù)有關(guān)	memset(outbuf, 0, outlen);	char *poutbuf = outbuf; //多加這個(gè)轉(zhuǎn)換是為了避免iconv這個(gè)函數(shù)出現(xiàn)char(*)[255]類型的實(shí)參與char**類型的形參不兼容	if (iconv(cd, &inbuf, &inlen, &poutbuf,&outlen) == -1)		return "";    std::string strTemp(outbuf);//此時(shí)的strTemp為轉(zhuǎn)換編碼之后的字符串	iconv_close(cd);	return strTemp;}//gbk轉(zhuǎn)UTF-8  std::string GbkToUtf8(const std::string& strGbk)// 傳入的strGbk是GBK編碼 {	return code_convert("gb2312", "utf-8",strGbk);}//UTF-8轉(zhuǎn)gbkstd::string Utf8ToGbk(const std::string& strUtf8){	return code_convert("utf-8", "gb2312", strUtf8);}//gbk轉(zhuǎn)unicode,"UCS-2LE"代表unicode小端模式std::string GbkToUnicode(const std::string& strGbk)// 傳入的strGbk是GBK編碼 {	return code_convert("gb2312", "UCS-2LE",strGbk);}//unicode轉(zhuǎn)gbkstd::string UnicodeToGbk(const std::string& strGbk)// 傳入的strGbk是GBK編碼 {	return code_convert("UCS-2LE", "gb2312",strGbk);}int main() {	//1、讀取"ANSI.txt"	ifstream in("ANSI.txt");	string strGbk;	in>>strGbk;	in.close();	cout<<strGbk<<endl;	int num = strGbk.size();//獲取兩個(gè)字符數(shù)，也是我字所占的字節(jié)數(shù)           unsigned char* p = (unsigned char*)strGbk.c_str();            for (int i = 0; i < num; i++)            {                printf("%0x", *p);                p++;            }  //輸出ced2 所以我的GBK編碼是0xced2        printf("/n"); 	//2、讀取"unicode.txt"	in.open("unicode.txt");	//過濾文本開始ff fe兩個(gè)字節(jié)	char a;	in>>a;	in>>a;	string strUnicode;	in >> strUnicode;	in.close();	cout<<UnicodeToGbk(strUnicode)<<endl;//轉(zhuǎn)成gbk輸出	num = strUnicode.size();      p = (unsigned char*)strUnicode.c_str();            for (int i = 0; i < num; i++)            {                printf("%0x", *p);                p++;            }  //輸出1162 因?yàn)槟J(rèn)是小端模式，所以我的unicode編碼是0x6211        printf("/n");     	//3、讀取"utf8.txt"	in.open("utf8.txt");	//過濾文本開始efbbbf三個(gè)字節(jié)	char b;	in>>b;	in>>b;	in>>b;	string strUtf8;	in>>strUtf8;	in.close();	cout<<Utf8ToGbk(strUtf8)<<endl;//轉(zhuǎn)成gbk輸出	 num = strUtf8.size();    p = (unsigned char*)strUtf8.c_str();            for (int i = 0; i < num; i++)            {                printf("%0x", *p);                p++;            }  //輸出e68891        printf("/n");          	return 0;}