What might a designer need to consider when choosing an appropriate energy source

one just the right power storage if it is not the right power storage it could over heat or catch fire

Explanation:

Explanation:

#include <cstdarg>

#include <iostream>

using namespace std;

double average ( int cnt, ... )

{

 va_list arg_avg;                    

 double sum_no = 0;

 va_start ( arg_avg, cnt );          

 for ( int x = 0; x < cnt; x++ )

 {

   sum_no += va_arg ( arg_avg, int ); // Adds the next value in argument list to sum.

 }

 va_end ( arg_avg );                  

 return sum_no / cnt;                      

}

int main()

{

 cout<< average ( 2, 12,13 ) <<endl;

}

Here va_list can declare variables which can hold variable number of values. va_start to initialize and va_end to clean up the list.