c++中的变参

 

# include <stdio.h>
# include <stdarg.h>

double sum_series(int num, ...);

int main()
{
 double d;

 d = sum_series(4, 0.5, 0.25, 0.125, 0.0625);

 printf("Sum of series is %f.\n", d);
 getchar();
 return 0;
}

double sum_series(int num, ...)
{
 double sum = 0.0, t;
 va_list argptr;

 /* 初始化argptr */
 va_start(argptr, num);

 /* 计算序列之和 */
 for( ; num; num--)
 {
  t = va_arg(argptr, double);
  sum = sum + t;
 }

 va_end(argptr);
 return sum;
}