Gettin Linker error

vince510 (55)
I'm new to using functions and trying to write a program to print out a calendar. While compiling in Dev C++ i'm getting a

[linker error] undefined reference to 'printCalendarHead(int&)

Here is the code. Why is this happening?

#include <iostream>
#include <fstream>
#include <iomanip>
#include <cstdlib>

using namespace std;

void printCalendarHead(int&);
void printCalendar(int&, int);

int main()
{

int currentMonth;
int inputYear;
int daysInMonth;
int dayOfWeek;

currentMonth = 1;

cout << "Input year you would like a calendar for: ";
cin >> inputYear;
cout << endl << endl << "Input day of week January 1st starts on 0-Sunday 6-Saturday: ";
cin >> dayOfWeek;
cout << endl << endl << setw(16) << inputYear << endl << endl << endl;


while(currentMonth <= 12)
{

printCalendarHead(currentMonth);

if(currentMonth == 4 || currentMonth == 6 || currentMonth == 9 || currentMonth == 11)
daysInMonth = 30;
else
{
if(currentMonth = 2)
{
if(inputYear % 4 == 0)
{
daysInMonth = 29;
}

daysInMonth = 28;
}

daysInMonth = 31;

}

printCalendar(dayOfWeek, daysInMonth);

cout << endl << endl;

currentMonth++;

}

return 0;
system("pause");

Last edited on
Disch (13742)
This means you never gave the 'printCalendarHead' function a body.
vince510 (55)
There is a body, I didnt post the code because i didnt want my post to be too long. here is the body for the function:

void printCalendarHead(/*in*/ int currentMonth)
{
if(currentMonth == 1)
cout << "January";

if(currentMonth == 2)
cout << "February";

if(currentMonth == 3)
cout << "March";

if(currentMonth == 4)
cout << "April";

if(currentMonth == 5)
cout << "May";

if(currentMonth == 6)
cout << "June";

if(currentMonth == 7)
cout << "July";

if(currentMonth == 8)
cout << "August";

if(currentMonth == 9)
cout << "September";

if(currentMonth == 10)
cout << "October";

if(currentMonth == 11)
cout << "November";

if(currentMonth == 12)
cout << "December";

cout << endl;

cout << setw(2) << "S" << " " << "M" << " " << "T" << " ";
cout << "W" << " " << "T" << " " << "F" << " " << "S" << endl;

cout << "--------------------" << endl;

}
Disch (13742)
That actually is not the body for that particular function because the parameter list is different. So the compiler treats them as two separate functions.

Note the difference:

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void printCalendarHead(int&);   // your prototype

void printCalendarHead(/*in*/ int currentMonth)  // your function body


The prototype is taking a reference (int&) and your function body is taking a normal int.

Change one of them so they match. I'd lose the reference.
vince510 (55)
good eye! thanks man. i will give it another shot.
vince510 (55)
worked a charm. programs not working though. could u take a look at this and tell me where its going wrong? the february month is still showing 31 days instead of 28.

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	if(currentMonth == 4 || currentMonth == 6 || currentMonth == 9 || currentMonth == 11)
			daysInMonth = 30;
		else
			{
				if(currentMonth == 2)
				{
					if(inputYear % 4 == 0)
					{
						daysInMonth = 29;
					}
					
					daysInMonth = 28;
				}

				daysInMonth = 31;

			}
Disch (13742)
daysInMonth is being set to 28 for February as you might expect.

But look what you're doing after that. Look closely.

Once you see the problem, you may notice you have the same problem with leap years.
Last edited on
vince510 (55)
haha that worked. placement error. it was automatically setting daysInMonth = 31. But now i'm having the same problem with the february if's.... looks like i did the same thing there too. Thanks again! 

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	if(currentMonth == 4 || currentMonth == 6 || currentMonth == 9 || currentMonth == 11)
			daysInMonth = 30;
		else
			{
                daysInMonth = 31;
                
				if(currentMonth == 2)
				{
  	                     daysInMonth = 28;         
					if(inputYear % 4 == 0)
					{
						daysInMonth = 29;
					}
					
				
				}

				

			}
vince510 (55)
Heres the finished program in case anyone is interested. Thanks for the help Disch.

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// This program prints a calendar based on user input
// vincent 6/25/09

#include <iostream>
#include <fstream>
#include <iomanip>
#include <cstdlib>

using namespace std;

void printCalendarHead(int&);
void printCalendar(int&, int);

int main()
{

    int currentMonth;
    int inputYear;
    int daysInMonth;
    int dayOfWeek;

	currentMonth = 1;
	
	cout << "Input year you would like a calendar for: ";
	cin >> inputYear;
	cout << endl << endl << "Input day of week January 1st starts on 0-Sunday 6-Saturday: ";
	cin >> dayOfWeek;
	cout << endl << endl << setw(16) << inputYear << endl << endl << endl;


	while(currentMonth <= 12)
	{

		printCalendarHead(currentMonth);		

		if(currentMonth == 4 || currentMonth == 6 || currentMonth == 9 || currentMonth == 11)
			daysInMonth = 30;
		else
			{
                daysInMonth = 31;
                
				if(currentMonth == 2)
				{
   	                   daysInMonth = 28;
   	                   
					if(inputYear % 4 == 0)
    	
						    daysInMonth = 29;
					
					
				
				}

				

			}

		printCalendar(dayOfWeek, daysInMonth);

		cout << endl << endl;

		currentMonth++;

	}	
    system("pause");
	return 0;
	

}

//****************************************************************************************
// print the heading for each month with null function


void printCalendarHead(/*in*/ int& currentMonth)
{
	if(currentMonth == 1)
		cout << "January";
	
	if(currentMonth == 2)
		cout << "February";
	
	if(currentMonth == 3)
		cout << "March";

	if(currentMonth == 4)
		cout << "April";

	if(currentMonth == 5)
		cout << "May";	

	if(currentMonth == 6)
		cout << "June";

	if(currentMonth == 7)
		cout << "July";

	if(currentMonth == 8)
		cout << "August";

	if(currentMonth == 9)
		cout << "September";

	if(currentMonth == 10)
		cout << "October";

	if(currentMonth == 11)
		cout << "November";

	if(currentMonth == 12)
		cout << "December";

	cout << endl;	

	cout << setw(2) << "S" << " " 
         << setw(2) << "M" << " " 
         << setw(2) << "T" << " "
	     << setw(2) << "W" << " " 
         << setw(2) << "T" << " " 
         << setw(2) << "F" << " " 
         << setw(2) << "S" << endl;

	cout << "--------------------" << endl;

}

//*********************************************************************************************
//printing the calendar

//*loop to print out days and keep track of 
//value to keep track of day of week if(dayOfWeek = 6)
						                 //cout << endl;


void printCalendar(/*inout*/ int& dayOfWeek,
		           /*in*/ int daysInMonth)

{

	int day, dayAlign;

	day = 1;	
	dayAlign = 0;	

	while(day <= daysInMonth)
	{
		while(dayAlign < dayOfWeek)
		{
			cout << "   ";
			dayAlign++;
		}
			
			
		cout << setw(2) << day;
		cout << " ";
		dayOfWeek++;
		day++;
        dayAlign++;

		if(dayOfWeek == 7)
			{
				cout << endl;
				
				dayOfWeek = 0;
			}

	}

}
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