我有一个枚举
enum ft_dev_type
{
SPI_I2C,
GPIO
};
我希望能够构造这样的字符串
std::string s = "enum =" + SPI_I2C; //would contain "enum = SPI_I2C"
为此,我正在尝试重载+运算符
std::string operator+(const ft_dev_type type) const
{
switch (type)
{
case SPI_I2C: return std::string("SPI_I2C");
case GPIO: return std::string("GPIO");
}
}
但是我得到
在字符串中添加“ ft_dev_type”不会追加到字符串中。
如何正确重载+运算符?
[edit]下面是课程
class driver_FT4222
{
public:
driver_FT4222() {}
enum ft_dev_type
{
SPI_I2C,
GPIO
};
std::string operator+(const ft_dev_type type) const //this line is probably wrong
{
switch (type)
{
case SPI_I2C: return std::string("SPI_I2C");
case GPIO: return std::string("GPIO");
}
}
void doSomething()
{
...
std::string s = "enum =" + SPI_I2C; //would contain "enum = SPI_I2C"
std::cout <<s;
...
}
}
答案 0 :(得分:5)
似乎您想要免费功能:
std::string operator+(const char* s, const ft_dev_type type)
{
switch (type)
{
case SPI_I2C: return s + std::string("SPI_I2C");
case GPIO: return s + std::string("GPIO");
}
throw std::runtime_error("Invalid enum value");
}
(与std::string
相似...)
但更好的IMO拥有to_string
std::string to_string(const ft_dev_type type)
{
switch (type)
{
case SPI_I2C: return std::string("SPI_I2C");
case GPIO: return std::string("GPIO");
}
throw std::runtime_error("Invalid enum value");
}
拥有
std::string s = "enum =" + to_string(SPI_I2C);