Define a function coordtransform() that transforms its first two input parameters xval and yval into two output parameters xvalnew and yvalnew. the function returns void.

C# program code:

function void coordtransform (int xval, int yval)
{
int xvalnew = transform(xval)
int yvalnew = transfomr(yval)
}

Explanation:
When we define new function we need to follow the rule:
function return_value name_of_function (input variables)

Inside of the code above we have another function that is called transform() and it has only one input parameter.