'foo' was not declared in this scope c++

Question

I\'m just learning c++ (first day looking at it since I took a 1 week summer camp years ago)

I was converting a program I\'m working on in Java to C++:

Answer 1

In general, in C++ functions have to be declared before you call them. So sometime before the definition of getSkewNormal(), the compiler needs to see the declaration:

double integrate (double start, double stop, int numSteps, Evaluatable evalObj);

Mostly what people do is put all the declarations (only) in the header file, and put the actual code -- the definitions of the functions and methods -- into a separate source (*.cc or *.cpp) file. This neatly solves the problem of needing all the functions to be declared.