std::lexical_cast - 有这样的事情吗?
C++ 标准库是否定义了这个函数,还是我必须求助于 Boost?
Does the C++ Standard Library define this function, or do I have to resort to Boost?
我在网上搜索,除了 Boost 什么都找不到,但我想我最好在这里问一下.
I searched the web and couldn't find anything except Boost, but I thought I'd better ask here.
推荐答案
仅部分.
C++11 有 std::to_string 用于内置类型:
C++11 <string> has std::to_string for the built-in types:
[n3290: 21.5/7]:
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);
返回: 每个函数返回一个 string 对象,其中包含其参数值的字符表示通过使用格式调用 sprintf(buf, fmt, val) 生成"%d"、"%u"、"%ld"、"%lu"的说明符,"%lld", "%llu",分别为 "%f"、"%f" 或 "%Lf",其中 buf 表示足够大小的内部字符缓冲区.
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.
还有以下相反的情况:
[n3290: 21.5/1, 21.5/4]:
int stoi(const string& str, size_t *idx = 0, int base = 10);
long stol(const string& str, size_t *idx = 0, int base = 10);
unsigned long stoul(const string& str, size_t *idx = 0, int base = 10);
long long stoll(const string& str, size_t *idx = 0, int base = 10);
unsigned long long stoull(const string& str, size_t *idx = 0, int base = 10);
float stof(const string& str, size_t *idx = 0);
double stod(const string& str, size_t *idx = 0);
long double stold(const string& str, size_t *idx = 0);
然而,没有任何通用的东西可以使用(至少 不是直到 TR2,也许吧!),而在 C++03 中什么都没有.
However, there's nothing generic that you can use (at least not until TR2, maybe!), and nothing at all in C++03.
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