(1)如何创建函数的std :: vector,以便可以执行以下操作:
int main ()
{
std::vector<????> vector_of_functions;
// Add an adding function into the vector
vector_of_functions.push_back(
double function (double a, double b) {
return a + b
}
);
// Add a multiplying function into the vector
vector_of_functions.push_back(
double function (double a, double b) {
return a * b;
}
);
// Use the functions
std::cout << "5 + 7 = " << vector_of_functions[0](5, 7); // >>> 5 + 7 = 12
std::cout << "5 * 7 = " << vector_of_functions[1](5, 7); // >>> 5 * 7 = 35
return 0;
}
虽然我想函数的返回值和参数可以是任何类型,但不必一定是。如果它们是固定类型,我很好。
(2)如何将这种std :: vector传递为函数的参数。
void func (std::vector<???> vof) {
std::cout << vof[0](5, 7);
};
int main ()
{
std::vector<????> vector_of_functions;
// Add an adding function into the vector
vector_of_functions.push_back(
double function (double a, double b) {
return a + b
}
);
// Add a multiplying function into the vector
vector_of_functions.push_back(
double function (double a, double b) {
return a * b;
}
);
// Call the function
func( vector_of_functions ); // >>> 12
return 0;
}
(3)除了函数是头文件中定义的类的方法之外,我该如何做。
.cpp代码与以前的代码相同,不同之处在于该函数为void ClassName::func(...);
.h代码将如下所示:
class ClassName {
public:
ClassName();
void func(????);
}
答案 0 :(得分:5)
如果可以使用C ++ 11 +,则可以使用std::function和std::bind或lambda。
所以,像这样:
using func = std::function<double(double, double)>;
using vfuncs = std::vector<func>;
vfuncs vf;
vf.push_back([](double first, double second) { return first + second; });
vf.push_back([](double first, double second) { return first * second; });
/* obj is some function, which member function you want to call */
vf.push_back([&obj](double first, double second) { return obj.op(first, second); });
答案 1 :(得分:1)
使用std::function<double(double,double)>
作为向量的模板参数,然后使用std::function<double(double,double)>
对象或可以转换为std::function<double(double,double)>
的对象(例如lamda):例如[](double a, double b) -> double { return a + b; }