用c编程，定义一个有20个元素的整型数组，求出下标为偶数的元素的平均值。

Question

如题所述

Answer 1

int a[]={1,2,3,...,19,20};
int tatal=0;//统计下标为偶数的元素的总额
int flag=0;//统计下标为偶数的元素的数量
for(int i=0;i<20;i++){
if(i%2==0&&i!=0){
flag++;
total=total+a[i];
}
float ver=total/flag;//求出平均值
}

Answer 2

#include<stdio.h>

void main()
{
int a[20];
int i;
int j = 0;
int avg;
int sum=0;
printf("please input 20 number\n");
for(i = 0; i < 20; i++)
{
scanf("%d",&a[i]);
if(i % 2 == 0)
{
j++;
sum += a[i];
}
}
avg = sum / j;
printf("下标为偶数的平均值为%d\n",avg);
}

Answer 3

#include<iostream>
using namespace std;

int Ave(int *pAry, int nLen) {
int sum = 0;
for (int i = 0; i < nLen; i+=2) {
sum += pAry[i];
}
return sum / ((nLen + 1) / 2);
}

int main() {
int ary[10] = {1,2,3,4,5,6,7,8,9,10};
cout << Ave(ary, 10) << endl;
return 0;
}