将数组传递给函数

我目前在一个介绍性的c++类中，正在处理排序数据的任务。我们最近讨论了structs，我决定使用structs来解决这个问题，而不是创建3个数组来保存数据文件中的信息。

我遇到的问题是当我试图将结构传递给函数时。这是我的错误：

analyze_data.cpp: In function ‘int main()’:
analyze_data.cpp:76: error: conversion from ‘weather*’ to non-scalar type ‘weather’ requested
analyze_data.cpp: In function ‘int find_pos_of_smallest(weather, int, int)’:
analyze_data.cpp:110: error: no match for ‘operator[]’ in ‘data[pos]’
analyze_data.cpp:110: error: no match for ‘operator[]’ in ‘data[pos_of_smallest]’

我不明白第76行的错误。我做了一些关于将结构传递给函数的研究，我发现在类型声明中添加了"&"。然而，我不知道它的作用，也不知道为什么我需要这样做，因为我们还没有在课堂上讨论过它。我也试过，但我只是犯了一系列不同的错误。所以我想我不会发布这些，只是从我所知道的开始。

这是我的代码

/*
Program name: Analyze data
Program discription:  This program will read a data file named data.txt.
This data file is expected to be formated in a specific way and contain
specific weather information.  The program will analyize this data and
return max, min temperatures, 'perfect days', how many cold fronts per
year, 10 coldest  and hottest days in a year and finally find the 5
median days of the year.
Date:  10/1/2012
*/
#include <iostream>
#include <fstream>
using namespace std;
/*
* Declare struct's here
*
*/ 
struct weather
{
string date;
int high;
int low;
};
/* 
*  Forward declaration of a function.  This declares the function,
*  but does not define it.  (Notice that there is no code, just
*  a function header with a semicolon after it.
*
*/
int find_pos_of_smallest (weather data, int start_pos, int end_pos);
/* Our main function.
*
* Parameters:
*    none
*
* Return value:
*    0 if we complete successfully, 1 if there was an error.
*/
int main()
{
//read the data file
ifstream weather_data("data.txt");
//declare array size, and then create array using struct
int days = 365;
weather data[days];
//store the data.txt in the array and then close the file
for (int i=0; i<days; i++)
{
weather_data >> data[i].date;
weather_data >> data[i].high;
weather_data >> data[i].low;
}
weather_data.close();
ofstream data_results ("results.txt");
// create the first 3 lines of the output reults in the following formated
data_results << "Assignment #5n"
<< "CS 1410/2000n"
<< "Jonathan Larsenn";
/*
for(int i=0; i<3; i++)
{
cout<<data[i].date << " "<<data[i].high << " " << data[i].low<<endl;
}
cout<<endl;
*/  
cout<<find_pos_of_smallest(data, 0, days)<<endl;

return 0;  //no error so return a zero  
}//end of program

/**** FUNCTIONS ****/
/* Write down exactly what the function will do (a postcondition).
* Write down what is required to use the function (any preconditions).
* Write down any other behavior or comments that will help a programmer.
*
* Parameters:   (list parameters by type and name, and explain them)
*   int example -- an example parameter
*
* Returns:
*   double -- an example return value
*/
/* Returns the position of the smallest value found in the specified
* subarray.  (Only the elements in the subarray
* between start_pos and end_pos inclusive are checked.)
*
* Parameters:
*    d - a data array
*    start_pos - the first position to check
*    end_pos - the last position to check
*/
int find_pos_of_smallest (weather data, int start_pos, int end_pos)
{
int pos_of_smallest = start_pos;
for (int pos = start_pos+1; pos <= end_pos; pos++)
if (data[pos].low < data[pos_of_smallest].low)
pos_of_smallest = pos;
return pos_of_smallest;
}