i need a little help

ap6118 · #1 06-Mar-2005, 23:07

the code down here is one i wrote to convert a digital date to an analogue one.if you compile and run it it will show the wrong month wich is probably due to the fact that arrays start at 0 and not at 1,to compensate for that i used a for loop ithin main to handle this and it worked exept that the program enters the loop and nver comes out.if anyone could fix this little problem for me i'll really appreciate it.

CPP / C++ / C Code:

//this program takes a digital date and outputs it in analogue!!!!!!

#include<iostream>
using namespace std;

				
void getinputs(int,int ,int);
void printoutputs(int, int, int);

int day,month,year;
 char *strmonth[12] = {"January", "February", "March", "April", "May", "June",
		    "July", "August", "September", "October", "November", "December"};

//Select day of Week



int main()
{

	cout << "THE PROGRAM WILL TRANSFORM YOUR DIGITAL DATE TO ANALOGUE"<<endl;
	cout << "please enter a digital date,seperated by spaces !!! "<<endl;

	getinputs(month,day,year);
	printoutputs(month,day,year);
	
		
		
	
return 0;
}

void getinputs(int,int,int)
{
	cin >>month>>day>>year;
}

void printoutputs(int, int, int)
{
	for (int i=1;i<=12;i++)
		*strmonth[i];
	cout <<"the date you entered was \n"<<"  "<<strmonth[month]<<"  "<<day<<"  "<<year<<endl;
	cout <<"let's do another \n";
}

LuciWiz · #2 07-Mar-2005, 07:49

Quote:

Originally Posted by ap6118

CPP / C++ / C Code:

//this program takes a digital date and outputs it in analogue!!!!!!
char *strmonth[12] = {"January", "February", "March", "April", "May", "June",
		    "July", "August", "September", "October", "November", "December"};

Doing this, you allocated 12 elements to your array, starting from index 0 to index 11.
Then, you try to access index 12 of the array - but that area of memory doesn't belong to you.

Quote:

Originally Posted by ap6118

CPP / C++ / C Code:

	for (int i=1;i<=12;i++)
		*strmonth[i];

Instead, start from 0 - this really is allocated, up until 11 (<=11, or <12).

So, what are you trying to do here? (I changed the indexes, as you see, so it won't crash or hang)

CPP / C++ / C Code:

	for (int i=0; i<12; i++)
		*strmonth[i];

Is this a test?

Well, as for the problem with the indexes, there is a quick fix: you have a 0-based array, but receive data that considers 1 as the starting index; just subtract 1 from the given data and you will have the 2 synchronized.

CPP / C++ / C Code:

	cout << "the date you entered was \n" << "  " << strmonth[month-1] << "  " << day 
		<< "  " << year << endl;
	cout <<"let's do another \n" << endl;

As a side note, I am really reticent about the use of global variables and cin, although if you are really good it might not get you into trouble. I guess in plain C global variables are OK (some say so, I don't agree

), but in C++ you might want to try and avoid them... (Now, I don't know which of them you are trying to use, since you mix them together. In C++ I wouldn't declare the function prototype in the same file - then again, I would use objects so the functions would really be methods

)

I see you are using formal parameters in your functions, but actually you are not using them

I'm guessing you had problems with the readout, because you gave the function an int, and the data didn't change after getinputs was called. The trick is to use passing by reference (please read this!)

You could do this by using pointers or references (in case you work in C++)

With pointers:

CPP / C++ / C Code:

//this program takes a digital date and outputs it in analogue!!!!!!

#include<iostream>
using namespace std;

void getinputs(int *, int *, int *);
void printoutputs(int, int, int);

//int day,month,year; I declared those in main
char *strmonth[12] = {"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"};

//Select day of Week

int main()
{
	int day, month, year;
	cout << "THE PROGRAM WILL TRANSFORM YOUR DIGITAL DATE TO ANALOGUE" << endl;
	cout << "please enter a digital date, separated by spaces !!! " << endl;

	getinputs(&month, &day, &year);
	printoutputs(month, day, year);

	return 0;
}

void getinputs(int * month, int * day, int * year)
{
	cin >> *month >> *day >> *year;
	//Some data validation would be in order 
}

void printoutputs(int month, int day, int year)
{
	/*
	for (int i=0; i<12; i++)
	{
	*strmonth[i];
	}
	*/
	cout << "the date you entered was \n" << "  " << strmonth[month-1] << "  " << day 
		<< "  " << year << endl;
	cout <<"let's do another \n" << endl;
}

Using references:

CPP / C++ / C Code:

#include<iostream>
using namespace std;

void getinputs(int &, int &, int &);
void printoutputs(int, int, int);

//int day,month,year; I declared those in main
char *strmonth[12] = {"January", "February", "March", "April", "May", "June",
"July", "August", "September", "October", "November", "December"};

//Select day of Week

int main()
{
	int day, month, year;
	cout << "THE PROGRAM WILL TRANSFORM YOUR DIGITAL DATE TO ANALOGUE" << endl;
	cout << "please enter a digital date, separated by spaces !!! " << endl;

	getinputs(month, day, year);
	printoutputs(month, day, year);

	return 0;
}

void getinputs(int & month, int & day, int & year)
{
	cin >> month >> day >> year;
}

void printoutputs(int month, int day, int year)
{
	/*
	for (int i=0; i<12; i++)
	{
		*strmonth[i];
	}
	*/
	cout << "the date you entered was \n" << "  " << strmonth[month-1] << "  " << day 
		<< "  " << year << endl;
	cout <<"let's do another \n" << endl;
}

I went along with the code you wrote so far so you would understand it, but you may want to stick to C or C++...
I hope this is OK.

Kind regards,
Lucian

ap6118 · #3 07-Mar-2005, 09:20

the pointer method make a lot more sence and is a lot more efficient.thanks a lot,i read a little more on pointers and i think i'm ready to play around with them now.
thanks a bunch
ciao

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