sum_series() 求一列数的指定个数的数和(5个数字的和)

 #include <stdio.h>
 #include <stdarg.h>
 /*用sum_series() 求一列数的指定个数的数和(5个数字的和)*/
 double sum_series(int num, ...);

 int main()
 {
     double s;
     s = sum_series(, 0.5, 0.25, 0.125, 0.06254, 2.0);
     printf("Sum of series is %2.8f.\n", s);
     return ;
 }

 double sum_series(int num, ...)
 {
     double sum= 0.0, t;
     va_list a;
     va_start(a, num);
     for(; num; num--)
     {
         t= va_arg(a, double);
         sum= sum+ t;
     }
     va_end(a);
     return sum;
 }