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c++11提供了to_string方法,可以方便的将各种数值类型转换为 字符串类型:

std::string to_string(int value);
std::string to_string(long int value);
std::string to_string(long long int value);
std::string to_string(unsigned int value);
std::string to_string(unsigned long long int value);
std::string to_string(float value);
std::string to_string(double value);
std::wstring to_wstring(int value);
std::wstring to_wstring(long int value);
std::wstring to_wstring(long long int value);
std::wstring to_wstring(unsigned int value);
std::wstring to_wstring(unsigned long long int value);
std::wstring to_wstring(float value);
std::wstring to_wstring(double value);

还提供了stoxxx方法,将string转换为各种类型的数据:

std::string str = "1000";
int val = std::stoi(str);
long val = std::stol(str);
float val = std::stof(str);

c++11还提供了字符串(char*)转换为整数和浮点类型的方法:

atoi: 将字符串转换为 int
atol: 将字符串转换为long
atoll:将字符串转换为 long long
atof: 将字符串转换为浮点数

c++11增加了unicode字面量的支持,可以通过L来定义宽字符 std::wstring wide_str = L”中国人”; //定义了宽字符字符串 将宽字符转换为窄字符需要用到condecvt库中的std::wstring_convert。 std::wstring_convert使std::string和std::wstring之间的相互转换变得很方便,如代码:

std::wstring wide_str = L"中国人";
std::wstring_convert<std::condecvt<wchar_t, char, std::mbstate_t>> converter(new std::codecvt<wchar_t, char, std::mbstate_t>("CHS");
std::string narrow_str = converter.to_bytes(wide_str);
std::wstring wstr = converter.from_bytes(narrow_str);
std::cout << narrow_str << std::endl;
wcout.imbue(std::locale("chs"));
std::wcout << wstr << std::endl;
std::cout << wstr.size() << " " << wstr.length() << endl;
std::cout << narrow_str.size() << " " << narrow_str.length() << endl;