Days since 1/1/1800,that day was Wednesday. Need to convert a date in the form mo/dy/year into this single number. Need a function to print out the day of the week, and a function to print out the date in the form month day, year where the month is completely spelled out. Need to write a program that uses this class to read data from a file and print the data in a new format on the standard output device. Having trouble converting a date in the form mo/dy/year ino the single number. The code I'm stuck on is in bold bellow, thanks in advance.

#include <iostream>
#include <fstream>
#include <cstdlib>
#include <string>
using namespace std;

// DaysFrom1800 Class Definition
class DaysFrom1800 {
public:
    DaysFrom1800();
    int numDaysFrom1800 (int day, int month, int year);
    int StartOfYear (int year);
    int fillDaysArray (int numberOfDates, int day[], int month[], int year[], string textArray[], DaysFrom1800 numbers []);
    void printDaysSince1800 ();
private:
    int daysSince;
};

// Prototypes
bool CalculateDate (int dayNumber, int day, int month, int year);
bool leapCheck (int year);
void prettyPrint (int numberOfDates, string textArray[], DaysFrom1800 numbers[]);

int main () {
// Declare Day, Month and Year Array to store Date Values
int day[200];
int month [200];
int year [200];

int numberOfDates = 0;
DaysFrom1800 numbers[200];
DaysFrom1800 dummy;
string textArray [200];

numberOfDates = dummy.fillDaysArray (numberOfDates, day, month, year, textArray, numbers);
for (int i=0; i <numberOfDates; i++) {
    cout << month[i] << "/" << day[i] << "/" << year[i] << endl;
}
for (i=0; i < numberOfDates; i++) {
    numbers[i].printDaysSince1800();
    cout << endl;
}
for (i = 0; i <numberOfDates; i++) {
    cout << textArray[i];
    cout << endl;
}
prettyPrint(numberOfDates, textArray, numbers);
return 0;
}

// Defualt Constructer for DaysFrom1800 Class
DaysFrom1800::DaysFrom1800() : daysSince (0) {
// Nothing to be done here...
}
[B]int DaysFrom1800::StartOfYear(int year){
int leapCount =0;
int days = 0;

// For loop to find the number of leap years
for (int i=1800; i < year; i++) {
        if (leapCheck(i))
            leapCount ++;
    }
 return((year-1800-leapCount)*365) + (leapCount*366);   


int daysPassed [12] =
{
     0,   // Jan 1
    31,   // Feb 1
    59,   // Mar 1 (non leap year)
    90,   // Apr 1 (non leap year)
   120,   // ...
   151,
   181,
   212,
   243,
   273,
   304,   // ...
   334    // Dec 1 (non leap year)
};

// takes a dayNumber and calculates the day/month/year
bool CalculateDate (int dayNumber, int &day, int &month, int &year)
{
   // make a first guess at the year
   int dayNumber= days;
   int yearGuess = dayNumber/365 + 1800;

   // calculate the day number of the start of that year
   int yearStart = StartOfYear (yearGuess);
   bool isLeapYear = leapCheck(yearGuess);
   int daysLeftInYear = dayNumber - yearStart;

   while (daysLeftInYear < 0)
      {
      yearGuess--;
      yearStart = StartOfYear (yearGuess);
      isLeapYear = leapCheck(yearGuess);
      daysLeftInYear = dayNumber - yearStart;
      }

   while ((isLeapYear && daysLeftInYear >= 365) || (!isLeapYear && daysLeftInYear >= 364))
      {
      yearGuess++;
      yearStart = StartOfYear (yearGuess);
      isLeapYear = leapCheck(yearGuess);
      daysLeftInYear = dayNumber - yearStart;
      }

   // now yearGuess is the correct year and 0 <= daysLeftInYear < 365 (or 366)
   year = yearGuess;

   int m;
   int daysLeftInMonth = daysLeftInYear ;

   for (m=0; m<12; m++)
      {
      // find the first month whose starting date is larger than daysLeftInYear
      if (daysLeftInYear < daysPassed[m])
         break;

      daysLeftInMonth = daysLeftInYear - daysPassed[m];
      }

   // m = month if this is not a leap year
   // daysLeftInMonth are the number of days past the begining of the previous month

   // first take care of the non-leap year case
   if (!isLeapYear || m == 1 || m == 2)
      {
      // either not a leap year or January or Febuary of a leap year
      month = m;
      day = daysLeftInMonth + 1;
      return true;
      }

   // for leap years, the extra day subtracts one from the days left in the month
   // and might move the day into a different month
   daysLeftInMonth --;

   if (daysLeftInMonth < 0)
      {
      m --;
      daysLeftInMonth = daysLeftInYear - daysPassed[m-1];

      if (m > 2)
         daysLeftInMonth --;
      }

   month = m;
   day = daysLeftInMonth + 1;
   return true;
	}
}
[/B]
int DaysFrom1800::numDaysFrom1800 (int day, int month, int year) {
int days = StartOfYear();
bool thisYear = leapCheck(year);
switch (month) {
case 1:
    days = days + day;
    break;
case 2:
    if (day < 28)
        days = days + 31 + day;
        if (thisYear)
            days = days + 31 + 29;
        break;
case 3:
    if (thisYear)
        days = days +31+29+ day;
        else
        days = days + 31 + 28 + day;
        break;
case 4:
    if (thisYear)
        days = days + 31 + 29 + 31 + day;
        else
        days = days + 31 + 28 + 31 + day;
        break;
case 5:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + day;
    else
        days = days +31 + 28 + 31 + 30 + day;
    break;
case 6:
    if (thisYear)
        days = days +31 + 29 + 31 + 30 + 31 + day;
    else
        days = days + 31 + 28 + 31 + 29 + 31 + day;
    break;
case 7:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + 31 + 30 + day;
    else
        days = days + 31 + 28 + 31 + 30 + 31 + 30 + day;
    break;
case 8:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + 31 + 30 + 31 + day;
    else
        days = days + 31 + 28 + 31 + 30 + 31 + 30 + 31 + day;
    break;
case 9:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 30 + day;
    else
        days = days + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 30 + day;
    break;
case 10:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + day;
    else
        days = days + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + day;
    break;
case 11:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + 30 + day;
    else
        days = days + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + 30 + day;
    break;
case 12:
    if (thisYear)
        days = days + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + day;
    else
        days = days + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + 30 + 31 + day;
    break;
}

return days;

}

/*void DaysFrom1800::printDaysSince1800 () {
cout << daysSince;
}*/

int DaysFrom1800::fillDaysArray (int numberOfDates, int day[], int month[], int year[], string textArray[], DaysFrom1800 numbers []) {

// Declare Stream and Open Text File
ifstream inStream;
inStream.open("in.txt");

// Test Input File
if (inStream.fail()) {
cerr << "Can't open file!\n";
exit(1);
}

// Declare and Initialize Index Variable
int i=0;

// Temp Character Array
char temp [100];

while (!inStream.eof()) {
// Get Dates from Text File Storing Info in day, month and year variables
inStream >> month[i] >> day[i] >> year[i];
inStream.get(temp, 100, '\n');
textArray[i]=temp;

// Increase Index by One
i++;
}

// Assign Index Value to numberOfDates variable to be returned in this function
numberOfDates = i;

// For Loop to Calculate Number of Days for Each Day and Store in Object Array
/*for (i=0; i<numberOfDates; i++) {
numbers[i].daysSince = numDaysFrom1800 (day[i], month[i], year[i]);
}
// Return Intever Variable numberOfDays
return numberOfDates;
}
*/
bool leapCheck(int year)
{
   // if the year is not 0 mod 4 then it is not a leap year
   if ((year % 4) != 0)
      return false;

   // every 4'th century IS a leap year
   if ((year % 400) == 0)
      return true;

   // every 4'th year that is not a century year is a leap year
   if ((year % 100) != 0)
      return true;
   else
      return false;
}

void prettyPrint (int numberOfDates, string textArray[], DaysFrom1800 numbers[]) {
    for (int i=0; i<numberOfDates; i++) {
    cout << "On ";
    // Call function to print date from day number
    cout << textArray[i] << '(';
    numbers[i].printDaysSince1800();
    cout << ')' << endl;
    }
}

Having trouble converting a date in the form mo/dy/year into a single number

I see you haven't yet grapsed the concept of encapsulation of data.

Why do you keep your months, years and days outside your class?
Wouldn't it be a lot better to have an array of dates instead of 3 arrays of the parts of that array?
That would enable you to move the parser into the class as well and avoid a lot of parameter passing.

Where does your function go wrong?
It looks overly complex. If you're loosing grasp of what your code is doing usually it's a good sign you'd better redesign it.

Think about how you should go about implementing the calculation on paper, then code to do that calculation.