Function Templates in C++ Troubles - c++

Question

I am trying to figure out what I am doing wrong here and its five in the morning and I have to turn this in today at 9 in the morning, so this is my last hope to come to you guys.
This program has to allow a user to enter 5 ints, 7 floats and 5 chars, which go into arrays which have to be coded via Function Templates. The numeric data than has to be bubble sorted and averaged. This has to be printed out Then I have to save the arrays to a .dat file and retrieve the data from the file and once again output it.
Errors: The Average is not recorded properly somehow so you get a nasty random memory output.
Only the int values are being saved to the text file, and I don't even know how to retrieve properly and print the retrieved values again.
Updated Code with fixed calc function
#include<iostream>
#include<iomanip>
#include<fstream>
using namespace std;
//Load data to array from Keyboard.
template <class T>
void load(T *a,const int n)
{
for(int i=0;i<n;i++)
cin>>a[i];
}
//Calc and Print the Average for a numeric array.
template <class T>
void calc(T *a,const int n,float *avg)
{
float b=0;
for (int i=1;i<n;i++)
{
b+=a[i];
}
*avg=b/n;
cout<<"The Average is: "<<*avg<<endl;
//Does not work. Prints out a random block of memory.
//Tried a couple things and still get he same bug.
}
//Sort the data array in ascending order.
template <class T>
void sort(T *a,const int n)
{
float t;
for(int i=0;i<n-1;i++)
for(int j=0;j<n-1;j++)
if (a[j]>a[j+1])
{
t=a[j];
a[j]=a[j+1];
a[j+1]=t;
}
}
//Save the array data to a text file.
template <class T>
void get(T *a,const int n)
{
ofstream outfile("C:\array.dat", ios::out);
for(int i=0;i<n;i++)
outfile << a[i]<< endl;
outfile.close();
//Only saves the first array (The ints)
}
//Retrieve the array data from the text file.
template <class T>
void save(T *a,const int n)
{
ifstream infile("C:\array.dat", ios::in);
for(int i=0;i<n;i++)
{
infile>>a[i];
}
infile.close();
}
/*Output should include the average for each of the two numeric arrays
along with all three arrays being printed out in ascending order twice,
once before the text file is saved and once after the array is retrieved
from the text file*/
int main()
{
const int n1=5,n2=7,n3=5;
int a[n1];
float b[n2];
char c[n3];
float avg[3];
int i;
cout<<"Enter 5 integers"<<endl;
load(a,n1);
sort(a,n1);
calc(a,n1,avg);
cout<<"Enter 7 floats"<<endl;
load(b,n2);
sort(b,n2);
calc(b,n2,avg+1);
cout<<"Enter 5 strings"<<endl;
load(c,n3);
cin.ignore(20, '\n');
sort(c,n3);
cout << endl;
cout<<"Output:"<<endl;
cout<<"The Integer array:" << endl;
for (i = 0; i < n1; i++)
cout << a[i] << " ";
cout << endl;
cout<<"The Float array:" << endl;
for (i = 0; i < n2; i++)
cout << b[i] << " ";
cout << endl;
cout<<"The String array:" << endl;
for (i = 0; i < n3; i++)
cout << c[i] << " ";
cout << endl;
save(a,n1);
get(a,n1);
save(b,n2);
get(b,n2);
save(c,n3);
get(c,n3);
//Need to print the now returned values here.
cout << endl;
//cin.get();
system("PAUSE");
return 0;
}
Sorry if half of this doesn't make sense. I am really tired.

Answer 1

For the average:
template <class T>
void calc(T *a,const int n,float *avg)
{
float b=0;
for (int i=1;i<n;i++)
{
b+=a[i];
}
avg[n]=b/n;
cout<<"The Average is: "<<avg[4]<<endl;
//Does not work. Prints out a random block of memory.
//Tried a couple things and still get he same bug.
}
you don't need an array of averages, you just want one average.
agv[n] = b / n; //assigns to the the n'th elemement of an array called avg.
try this instead:
*avg = b/n
And for printing it out, just '*avg' also.
When you call calc, try:
float avg1;
calc(b,n4,&avg1);
When you see & and *, read them as the following:
& address of
* contents of address

Answer 2

you only need three averages, one for the 5 ints, one for the 7 floats and one for the 5 chars.
float avg[4]; // should be: float avg[3];
You seem to be passing the wrong parameters to each of the calc functions. When you call calc for the ints, use:
calc(a,n1,avg);
for floats:
calc(b,n2,avg+1);
for chars:
calc(c,n3,avg+2);
n4=2; is not relevant to anything, you can delete n4.

Answer 3

When you open the file, you will need to specify ios:app which appends to the existing file. Without that, every time you write to the file anything that existed in it before will be thrown away.
ios::out | ios::app
So, first write just use ios::out, after that include ios::app