C语言通过下标和通过指针循环数组求平均数

#include "stdafx.h"

double getAvg(int* arr,int length);
double getAVG(int* arr,int length);
int main(int argc, char* argv[])
{

  int a[]={10,30,50,80,90};
  int length=sizeof(a)/sizeof(int);
  double res=getAVG(a,length);
  printf("%lf",res);
  return 0;
}



double getAvg(int* arr,int length){
  int sum=0;
  for(int i=0;i<length;i++){
    sum+=arr[i];
  } 
  return (double)(sum/length);
}

double getAVG(int* arr,int length){
  int sum=0;
  for(int i=0;i<length;i++){
    sum+=*arr;
    arr++;
  }
  return (double)(sum/length);
}

输出

52.000000