Passing # of Arguments

[80Degrees]

I was wondering if there were a function to pass the # of arguments in a parameter to a value of a variable.

For instance, lets say I want a program that does averages, the main function collects the #'s, and then theres a getAvg function which does the math

Is there a way for one of the arguments in getAvg to be the # values being passed to it?

[laserlight]

You could store the numbers in say, a std::vector and when the data collection is done, just calculate the average of the numbers in the container.

[stober]

you could write getAvg() to use a variable number of arguments, but the std::vector is a lot better and easier to implement solution for c++ programs. There must be at least one non-variable argument. and you need to devise for that function to know where the last argument is -- maybe pass -1 or something else that will not occur normally in the other arguments. for variable arguments you need to use functions in stdarg.h (http://msdn2.microsoft.com/en-us/library(d=robot)/kb57fad8.aspx) . Scroll down the page of that link and you will find some example programs.


int getAvg(int a, ...);

int main()
{
int n = getAvg(1,2,3,4,5,6,-1);
}

[exterminator]

Variadic functions (http://www.gnu.org/software/libc/manual/html_node/Variadic-Functions.html)

[laserlight]

The problem I see is that for "the main function collects the #'s" to work, there must be some way to store the numbers. Or, if the average is the arithmetic mean, one can just sum and keep a counter of the number of numbers input, then divide. That doesnt even need a container (aside from the sum), but "average" here is rather vague.