C ++ 11标准明确地说（ 21.5 / 7 ）：

The C++11 Standard explicitely says (21.5/7):

返回：每个函数返回一个字符串对象，该对象包含其参数值的字符表示，该参数将通过调用具有格式说明符％d，％u的sprintf（buf，fmt， ％ld，％ld，％ld，％ld，％ld，％ld，％ld，％ld / p>

Returns: Each function returns a string object holding the character representation of the value of its argument that would be generated by calling sprintf(buf, fmt, val) with a format specifier of "%d", "%u", "%ld", "%lu", "%lld", "%llu", "%f", "%f", or "%Lf", respectively, where buf designates an internal character buffer of sufficient size

以此顺序声明的函数：

string to_string(int val);
string to_string(unsigned val);
string to_string(long val);
string to_string(unsigned long val);
string to_string(long long val);
string to_string(unsigned long long val);
string to_string(float val);
string to_string(double val);
string to_string(long double val);

因此，您无法控制结果字符串的格式。

Thus, you cannot control the formatting of the resulting string.