Calendar ALMOST DONE!!!

Howdie all.

Up front I'd like to thank your for taking the time to read this.
Here is my problem , I wrote a program that takes the date entered as MMDDYYYY, and it converts it to for example

01012000 to January 1, 2000..

Here is my problem when I type in the about input 01012000 I get January 20 2000...I know its a math error, but for the life of me I cannot find it...any help would be appreciated.

Oh and there is one more thing , If at all you could give suggestions on how to shorten the code, i would be very grateful, thanks again. Heres the code

Code:

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#include <iostream>
#include <iomanip>
#include <string>
using namespace std;

void input();
bool checkdigit();
bool checklength();
bool checkday();
bool checkmonth();
int contoint();
int contointd();
int contointy();
void printdate();

int n,a,b,c;
string date, stop, day, year, month;
bool ok;

int main()
{
        input();

        while (date != "stop")
        {
                ok = checklength();
                if (ok == true)
                        ok = checkdigit();
                if (ok == true)
                {
                        month = date.substr (0,2);
                        day = date.substr (2,2);
                        year = date.substr (4,4);
                        a = contoint();
                        b = contointd();
                        c = contointy();
                        ok = checkmonth();
                        if (ok = true)
                        {
                                ok = checkday();
                                if (ok == true)
                                        printdate();
                        }
                }

                input();
        }
        return 0;
}

void input()
{
        cout << endl<< "Enter Stop to quit" << endl << "Enter the date in the form of MMDDYYYY or MDDYYY :";
                cin >> date;
}

bool checklength()
{
        if (date.length() == 7)
                date = "0" + date;
        if (date.length() != 8)
        {
                cout << "Your Lenght is wrong" << endl;
                return false;
        }
       
        return true;
}

bool checkdigit()
{
        n = 0;
        while (n <=7)
        {
                if (date[n] >= 48 && date[n] <= 57)
                        n++;
                else n = 50;
                        if(n == 50 || n == 0)
                        {
                                cout << "Use all numbers"<< endl;
                                return false;
                        }
        }
        return true;
}

int contoint()
{
        int a = 0, x = 0;
        int len = month.length();
        while (x < len)
        {
                a = a * 10 + int (month[x]) - 48;
                x++;
        }
        return a;
}

int contointd()
{
        int b = 0, x=0;
        int len = day.length();
        while (x < len)
        { b=b * 10 + int (year[x]) - 48;
        x++;
        }
        return  b;
}

int contointy()
{
        int c = 0, x = 0;
        int len = year.length();
        while (x < len)
        {
                c = c * 10 + int ( year [x]) - 48;
                x++ ;
        }
        return c;
}

bool checkmonth()
{
        if (a == 0 || a > 12)
        {
                cout << "Month is Bad."<< endl;
                return false;
        }
                return true;
}

bool checkday()
{
        if (b == 0 || b > 31)
        {
                cout<<" Day is Bad." << endl;
                return false;
        }
        if (a == 2 && b == 29)
        {
                if (c % 400 == 0)
                        return true;
                else if (c % 100 == 0)
                {
                        cout << " Day is not correct." << endl;
                        return false;
                }
                else if ( c % 4 == 0 )
                        return true;
                else
                {
                        cout << "The day is not correct." << endl;
                        return false;
                }
        }
        if (a == 4 || a == 6 || a == 9 || a == 11)
        {
                if (b > 30)
                {
                        cout << " Day is bad." << endl;
                        return false;
                }
        }
        return true;
}
        void printdate()
        {
                if (a == 1)
                        cout <<" January";
                else if (a == 2)
                        cout << "February";
                else if (a == 3)
                        cout << "March";
                else if (a == 4)
                        cout << "April";
                else if (a == 5)
                        cout << "May";
                else if (a == 6)
                        cout << "June";
                else if (a == 7)
                        cout << "July";
                else if (a == 8)
                        cout << "August";
                else if (a == 9)
                        cout << "September";
                else if (a == 10)
                        cout << "October";
                else if (a == 11)
                        cout << "November";
                else if (a == 12)
                        cout << "December";
                cout << b<<" ,  " << c<< endl;
        }

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Right here:

Code:

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int contointd()
{
        int b = 0, x=0;
        int len = day.length();
        while (x < len)
        { b=b * 10 + int (year[x]) - 48;
        x++;
        }
        return  b;
}

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That should be day[x] :)

> int contoint();
> int contointd();
> int contointy();
> void printdate();
Pass some parameters to these functions
Then you can get rid of all your global variables.

> int n,a,b,c;
And while you're at it, give them better names.

> if (ok = true)
1. you meant ==
2. since it is a boolean, you should just say either

Code:

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if ( ok ) // its all good
if ( !ok ) // its all bad

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In fact you can reduce the whole thing to

Code:

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if ( checkmonth() && checkday() ) printdate();

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> if (date[n] >= 48 && date[n] <= 57)
Don't assume you're using the ASCII character set
if (date[n] >= '0' && date[n] <= '9')
is both more readable and more portable

> a = a * 10 + int (month[x]) - 48;
Basically the same code in 3 different functions
With some parameters, you could so easily make all 3 the same function.

> if (a == 1)
> cout <<" January";
Use an array

Code:

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static char *months[] = { "January", .... };
cout << months[a-1];

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