日常的开发中经常会用到类型的相互转换，这里记录一下；

1, int转hex

std::string IntToHex(int value) {stringstream ioss;ioss << std::hex << value;string temp;ioss >> temp;return temp;}

2, int转hex 设置宽度

std::string intToHexString(int input, int width) const
{std::stringstream convert;convert << std::hex  << std::setfill('0');convert << std::setw(width) << input;return convert.str();
}

3，int to string 可设置宽度

// default width = 1
std::string intToString(int input, int width = 1) const;std::string intToString(int input, int width) const
{std::stringstream convert;convert << std::dec << std::setfill('0');convert << std::setw(width) << input;return convert.str();
}

4.string to int

int stringToInt(std::string input) const
{int retVal = 0;std::stringstream convert(input);convert << std::hex;convert >> retVal;return retVal;
}

5. string转wstring

std::wstring s2ws(const std::string& s) {setlocale(LC_ALL, "chs");size_t _dsize = s.size() + 1;wchar_t* _dest = new wchar_t[_dsize];wmemset(_dest, 0, _dsize);const char* _source = s.c_str();mbstowcs(_dest, _source, _dsize);std::wstring result = _dest;delete[] _dest;setlocale(LC_ALL, "C");return result;
}

6. wstring转string

std::string ws2s(const std::wstring& ws) {std::string cur_locale = setlocale(LC_ALL, nullptr);setlocale(LC_ALL, "chs");size_t _dsize = 2 * ws.size() + 1;char* _dest = new char[_dsize];memset(_dest, 0, _dsize);const wchar_t* _source = ws.c_str();wcstombs(_dest, _source, _dsize);std::string result = _dest;delete[] _dest;setlocale(LC_ALL, cur_locale.c_str());return result;
}

7. char*转hex

void strtohex(const char* str, int slen, char* buff, int len) {assert(slen == len * 2);for (int i = 0; i < len; i++) {char strhex[5] = "0x00";strhex[2] = str[i * 2];strhex[3] = str[i * 2 + 1];buff[i] = (byte)strtol(strhex, NULL, 16);}}

8. unsigned转hex

std::string UintToHex(unsigned int value) {stringstream ioss;ioss << std::hex << value;string temp;ioss >> temp;return temp;}

9. float转char*

char * float2str(float val, int precision, char *buf) {char *cur, *end;sprintf(buf, "%.6f", val);if (precision < 6) {cur = buf + strlen(buf) - 1;end = cur - 6 + precision;while ((cur > end) && (*cur == '0')) {*cur = '\0';cur--;}}return buf;}

10. string转unsigned int

unsigned int string2Uint(string str) {unsigned int result(0);//最大可表示值为4294967296（=2‘32-1）//从字符串首位读取到末位（下标由0到str.size() - 1）for (int i = str.size() - 1; i >= 0; i--){unsigned int temp(0), k = str.size() - i - 1;//判断是否为数字if (isdigit(str[i])){//求出数字与零相对位置temp = str[i] - '0';while (k--)temp *= 10;result += temp;} else//exit(-1);break;}return result;}