how to generate random isotropic vectors using R?

How do I find the cross product of two vectors in C++ using a function? The two vectors are two 1-D arrays of a class.

• What i mean by vector here is a 1-d array of size length 3(not the vector container in CPP). Means float a[3],b[3],c[3]; Now suppose we want to store cross product of a and b into array c, how will we do it using a function? The function arguments (inputs) are a[3],b[3] and it should return (output) array c[3]. Can we have return value as an array?

• Answer:

  No, you cannot return an array. However, you can make a function that a reference to 3 arrays. The function would make three assignments. A function that accepts a single array of 5 ints would look like this: void cool( int (&runnings) [5]) Let's assume the arguments are arrays called a and b, and the output (also the last parameter to the function) is called c. The three equations would look similar to: c[0] = a[1] x b[2] - a[2] x b[1] I can't remember the exact order but every resultant component is the difference between the products of each of the two other components. Sounds fancy, but I'm sure you get what I mean. You could consider making your own vector class which will allow you to return that from a function. Also would result in clearer to understand code. Good luck.