need help with Funcation all around

[redmondtab]

I have done this . Write a C program that will accept keyboard
input and display a loan amortization schedule back on the screen. The
program should ask for the Loan Amount (real number), Term of the Loan
in months (integer), and the Interest Rate (real number); the input data
should be validity checked. The output should list a heading showing the
input values, then a separate line indicating Payment Number, Loan
Balance, Payment Amount, Amount to Principle, Amount to Interest, New
Balance for each payment. A loop should be used to display the
amortization list. The payment amount is calculated using the formula:
[ (1 + i / 12) ** n * (i / 12 * a) ] / [ (1 + i / 12) ** n – 1 ]
where i=interest rate, n=number of months, a=current balance
After completing one occurrence the program should exit.
and took it and modified to do 2. Due by the end of week 4. Modify the C program from assignment 1 to use function calls and pass parameters. The following functions should be used:
Collect Input (collect and validate input values),
Calculate a Payment, and
Write Amortization Line
i'm having issues to get my main program to read my funcation. I know that I'm missing the statement to call them in. But I also know that i have to may items to send out data from one funcation to the next. This is done all online so I do not have a teacher or anyone to ask question to. I need some help. I seem to have hit a brick wall and it keeps grow up and up.

#include <stdio.h>
#include <math.h>
 
 
double CollectInput (double a, double i, int n, int Numberofmonths,  int PaymentNumber, int count);
double Calculate (int n,double a, double i,double PaymentAmount,double PaymentNumber, 
         double Numberofmonths, int count, double AmountInterest, 
         double AmountPrinciple, double LoanBlance); 
double Amortization (double a, double InterestRate, double LoanAmount, int PaymentNumber, 
             double AmountPrinciple, double AmountInterest, double LoanBlance, double PaymentAmount); 
 
 
main ()
{
 
int   TermLoan,  // length of the loan
         PaymentNumber,  //number of payments made
          Numberofmonths, //Number of months in the loan
          count,
          n,c; //Letters used for the calculations
double   AmountPrinciple, //Amount paid on principle
         AmountInterest,  //amount paid to interest
         LoanBlance, //amount owed on loan\ count,
         CurrentBlance,
          LoanAmount, //amount of the loan  
         InterestRate, //interest rate on loan
          returnedValue,  a,i,
           PaymentAmount;  //amount paid to loan 
 
 
  CollectInput  (a, i, n, Numberofmonths, PaymentNumber, count);
  returnedValue = CollectInput (a, i, n, Numberofmonths, PaymentNumber, count);
  Calculate (n, a, i, PaymentAmount, PaymentNumber, Numberofmonths, count, 
            AmountInterest, AmountPrinciple, LoanBlance );
 
 
   Amortization (a, InterestRate, LoanAmount, PaymentNumber, AmountPrinciple, 
                 AmountInterest, LoanBlance, PaymentAmount);                         
 
 
 
printf ("hit enter to end");
getchar ();
getchar ();
return 0;         
}
 
//****************************************************************      
//Start of the function to collect data
//****************************************************************
double CollectInput (double a, double i, int n, int Numberofmonths, int PaymentNumber, int count)
     {
      int TermLoan,
           c ;
      double LoanAmount,
             InterestRate,
             CurrentBlance;
 
        while (scanf("%lf%d%lf", &LoanAmount, &TermLoan, &InterestRate) != 3
                     || (LoanAmount < 0 || TermLoan < 0 || InterestRate < 0 ))
          {
             while ((c = getchar()) != '\n' && c != EOF);
             printf ("Please re-enter in loan amount, Term of Loan in months and Interest Rate.\n");
             }
 
 
             CurrentBlance = LoanAmount;
               Numberofmonths = TermLoan; 
               i = InterestRate/ 100;    
               n = Numberofmonths;
               a = CurrentBlance;
                PaymentNumber = 0;
                count = 0; 
 
                return i, n, a, PaymentNumber, count; 
   }  //end of collect data
 
 
//********************************************************************
//Start of Calculate function
//*************************************************************
 double Calculate (int n,double a, double i,double PaymentAmount,double PaymentNumber, 
         double Numberofmonths, int count, double AmountInterest, 
         double AmountPrinciple, double LoanBlance)              
   {
 
 
         PaymentAmount = ((i/12*a)/(1-pow((1+(i/12)),-n)));            
 
            while(PaymentNumber < Numberofmonths)
             {
 
             PaymentNumber++; //Start number of months for amortization schedule
             count++;
             AmountInterest = a  * (i/12);  
             AmountPrinciple = PaymentAmount - AmountInterest;
             LoanBlance = a - AmountPrinciple;
             a = LoanBlance; 
             return a, PaymentNumber, LoanBlance, PaymentAmount, 
                   AmountPrinciple, AmountInterest; 
                }//end of while loop 
   } //end of Calculate Function
 
 
//*********************************************************************
//State of print function
//************************************************************
double Amortization (double a, double InterestRate, double LoanAmount,  int PaymentNumber, 
        double AmountPrinciple, double AmountInterest, double LoanBlance, double PaymentAmount)
{
          printf ("\amortization Schedule\n");
            printf ("_____________________\n");
           printf ("CurrentBlance %.2f\n", a);
           printf ("InterestRate %.2f\n", InterestRate); 
          printf ("PaymentNumber %d\n",  PaymentNumber);
          printf ("LoanBlance  %.2f\n", LoanBlance);
          printf ("PaymentAmount %.2f\n", PaymentAmount);
          printf ("AmountPrinciple %.2f\n", AmountPrinciple);
          printf  ("AmountInterest %.2f\n", AmountInterest);
          printf ("_______________________\n\n");
 
          return 0;
} //end of Amortization print function