从另一个函数f0（x，y）定义函数f1（x）对象，但将y设置为固定值c ++

Question

Suppose I have a function

  void f0(double x, double parameters[]) { ... }

and I want to define a function object

  std::function <void (double x) >f1 

such that, for example, f1(x) = f0(x,a) where a is a specified set of parameters (eg double parameters[4] = {1.0, 2.9, 6.2, 2.1} )

How would I do this? My thoughts are to try to have a function that inputs a outputs f1, but I'm not sure how to do this.

The motivation of this is that, in essence, I have yet another function FUNC in a library, that inputs a function with a single double input, but I want more flexibility to add parameters to that function

Answer 1

This is very simple with a lambda:

std::function<void(double)> f1 =
    [&parameters](double x) { f0(x, parameters); };

Alternatively, you could use std::bind .

using namespace std::placeholders;
std::function<void(double)> f2 = std::bind(f0, _1, parameters);

But I much prefer lambdas for almost any situation.