接受一个指针

#include <stdio.h>



/* function declaration */

double getAverage(int *arr, int size);



int main () {



   /* an int array with 5 elements */

   int balance[5] = {1000, 2, 3, 17, 50};

   double avg;



   /* pass pointer to the array as an argument */

   avg = getAverage( balance, 5 ) ;



   /* output the returned value  */

   printf("Average value is: %f\n", avg );

   return 0;

}



double getAverage(int *arr, int size) {



   int  i, sum = 0;       

   double avg;          



   for (i = 0; i < size; ++i) {

      sum += arr[i];

   }



   avg = (double)sum / size;

   return avg;

}