怎样定义一组重载函数计算数组各元素的和，要求重载函数能处理的数组类型包括int,double和long？

#include
using namespace std;
void print(double sum);
void print(long sum);
void print(int sum);
int main()
{
int sum;
cout<<print(sum)<<endl;
return 0;
}
void print(double sum)
{
int i;
double a[5]={1.0,2.0,3.0,4.0,5.0};
for(i=0;i<5;i++)
sum=sum+a[i];
}
void print(long sum)
{
int i;
long a[5]={1l,2l,3l,4l,5l};
for(i=0;i<5;i++)
sum=sum+a[i];
}
void print(int sum)
{
int i,a[5]={1,2,3,4,5};
for(i=0;i<5;i++)
sum=sum+a[i];
}

一般这么写
int sum(int * arr, int n)
{
int sum = 0;
for (int i = 0; i < n; i++) sum += arr[i];
return sum;
}
long sum(long * arr, int n)
{
long sum = 0;
for (int i = 0; i < n; i++) sum += arr[i];
return sum;
}
double sum(double * arr, int n)
{
double sum = 0;
for (int i = 0; i < n; i++) sum += arr[i];
return sum;
}
主程序
int main()
{
double a[5]={1.0,2.0,3.0,4.0,5.0};
double r = sum(a, 5);
cout << r;
别的类似
}

把void print(double sum);
void print(long sum);
void print(int sum);
改成
double print(double sum);
long print(long sum);
int print(int sum);