How to write functions with variable arguments in C

Question

I want to write a function with variable number of arguments in c..can some one guide me..

Answer 1

Such function calls ellipses: http://www.learncpp.com/cpp-tutorial/714-ellipses-and-why-to-avoid-them/

Because ellipses are rarely used, dangerous, and we strongly recommend avoiding their use, this section can be considered optional reading.

If you nevertheless need such a function, take a look at this example (the point is va_list):

double FindAverage(int nCount, ...)
{
    long lSum = 0;

    // We access the ellipses through a va_list, so let's declare one
    va_list list;

    // We initialize the va_list using va_start.  The first parameter is
    // the list to initialize.  The second parameter is the last non-ellipse
    // parameter.
    va_start(list, nCount);

    // Loop nCount times
    for (int nArg=0; nArg < nCount; nArg++)
         // We use va_arg to get parameters out of our ellipses
         // The first parameter is the va_list we're using
         // The second parameter is the type of the parameter
         lSum += va_arg(list, int);

    // Cleanup the va_list when we're done.
    va_end(list);

    return static_cast<double>(lSum) / nCount;
}