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sys0p · Oct 15th, 2004, 3:07 PM

Hi,
As I am learning C++ i've decided to post my code to help anyone out there. Of course most of you will be godlike programmers, but for us, the newbs this might help

Below is some code to allow the user to input 5 integer numbers into two arrays, array1 and array2.

If the numeber's are the same i.e

array1 = { 1, 2, 3, 4, 5 };
array2 = { 1, 2, 3, 4, 5 };

Then the message "The array's are equal" is output, else the message "The array's are not equal" is output.

(Toggle Plain Text)

#include <iostream.h>

int array1[5];
int array2[5];

main()
{
	cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n';
	cout << "Please enter 5 numbers into this array: ";
	cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4];
	cout << "and do enter 5 numbers into this array: ";
	cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4];

	int i;

	for( i = 0; i < array1[5]; i++ )
	{
 if(array1[i] != array2[i]) {
 cout << "The array's are not equal" << '\n';
 break;
 }
	cout << "The array's are equal";
	}

	return(0);
}

If there are any mistakes here please point them out. After all the purpose of this code is to help us learn

Oh, maybe some suggestions as how to improve the program.

One would be to say:

if size of array1 is not equal to size of array2, then break.

Obviously. But I haven't implemented it in the code yet.

Cheers!

kilgayne · Oct 15th, 2004, 3:25 PM

iostream.h sucks
conio.h rulez \o/

(Toggle Plain Text)

cprintf("I guess this could eventually help n00bs.\r\nDon't give up!");

Das Bruce · Oct 15th, 2004, 11:00 PM

I'm not sure if these are errors but you might want to look into it.

(Toggle Plain Text)

for( i = 0; i < array1[5]; i++ )

array1[5] is actually the 6th element.

(Toggle Plain Text)

int i;
for( i = 0;

could be compressed into

(Toggle Plain Text)

for(int i=0;

Mjordan2nd · Oct 15th, 2004, 11:18 PM

Actually, my compiler complains when I compress the for loop like that. Don't know why.

Das Bruce · Oct 16th, 2004, 12:46 AM

What are you using?

I use DevC++ which comes with gcc. DevC++ home

sys0p · Oct 16th, 2004, 5:11 AM

(Toggle Plain Text)

#include <iostream.h>

int array1[5];
int array2[5];

main()
{
cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n';
cout << "Please enter 5 numbers into this array: ";
cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4];
cout << "and do enter 5 numbers into this array: ";
cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4];

int i;

for( i = 0; i < array1[5]; i++ )
{
 if(array1[i] != array2[i]) {
 cout << "The array's are not equal" << '\n';
 break;
 }
cout << "The array's are equal";
break;
}

return(0);
}

That should work. I swear the last bit worked for me, but I probably edited it by mistake. Sorry

It should work now. I'm using Dev C++ 4

Cheers!

sys0p · Oct 16th, 2004, 5:14 AM

Quote:

array1[5] is actually the 6th element.

Hey, uh that's why you say that i is less than array[5] which is the 6th element. but it doesnt stop you adding more than 5 numbers!? I can't figure out why :/

Ooble · Oct 16th, 2004, 6:34 AM

You want:

(Toggle Plain Text)

for (i = 0; i < 6; i++) ...

You want it to go through 6 times, not until it becomes higher than whatever's in array[5].

mici · Oct 16th, 2004, 7:17 AM

Ooble is right...
you've been checking if your iterator is lower than the member no. 5 in your array...
by default array[5] is not defined and can be any number until you set it...
i.e it can be 4331 or 0 or -234 ... this is why your "for" loop won't work as it should...
The probable reason why it ends after 5 loops is that since both array1 and array2 have not been defined and as such are probably bigger positive nums left from some process before the loop finds that they are not equal and breaks there...
another thing is that your program shouldn't work at all...
if you observe more closely
you'll see that the "if" checks if the array1[i] is equal to array2[i] and then if they aren't equal function breaks from the for loop wich is ok, however if they are equal the function also breaks and it never checks for "i" larger than "0".

So actualy your program works fine ... it just checks if element 0 from both arrays are equal and displays result and then breaks...

Now for the solution you can eather try to repair your code ... remove the breaks and iclude counter for num of equals or !equals...
The other solution, much faster and easier to progam is to use memcmp()
like this
memcmp(array1, array2, 5*2);
5*2 is because int takes 2 bytes so if you used chars it would be just 5 and if you used doubles it would be 5*4.
memcmp will return 0 if both fields are equal....
Hope this helps a little.

sys0p · Oct 16th, 2004, 11:07 AM

Hey,
Thanks for the replies!

Quote:

You want it to go through 6 times, not until it becomes higher than whatever's in array[5].

Well supposing you didn't know how big your array was? How would you tell the counter to exit when it hit the last element in the array? Suppose you had an array my_array[100] and you only type in 5 elements, and your counter is set to for( i = 0; i < 100; i++ ) then it would output weird results. Or am I being totally stupid here?

Logic says that I am being stupid because the iterator goes through 99 elements, then to the last element \0 in the array. So it goes over each element, if the first 5 have been typed it goes through:

array1[0]
array1[1]
...
array1[4] //Hits the last value actually entered into the array
array1[5]
array1[99] //Iterates through all the rest of the elements, which contain nil
array1[100] //Hits the last element which is \0

So either way, if you enter 5 values or 99 it still iterates through the array. Right?

Quote:

you've been checking if your iterator is lower than the member no. 5 in your array...
by default array[5] is not defined and can be any number until you set it...

OK I think I see the problem.

Actually I had a nasty feeling that it was a fluke

I was about to post and say that how could it compare array1[i] and array2[i] if you didn't create a loop for array2. Or am I being stupid here?

Quote:

So actualy your program works fine ... it just checks if element 0 from both arrays are equal and displays result and then breaks...

Please correct me if I am wrong: How can this be when your iterator starts at 1. That means that it checks array[1] first and not array[0], if you get what I mean?

Quote:

The other solution, much faster and easier to progam is to use memcmp()
like this
memcmp(array1, array2, 5*2);
5*2 is because int takes 2 bytes so if you used chars it would be just 5 and if you used doubles it would be 5*4.
memcmp will return 0 if both fields are equal....

Sorry, I know nothing about memcmp because I haven't ever heard about it. It's far beyond the scope of my knowledge. I still have to reach that chapter in the book i'm reading, Practical C++ Programming, 1st Ed. Unfortunately. But thanks for pointing that out.

TO CLEAR UP ON A FEW THINGS:

#1
In the for loop:

(Toggle Plain Text)

for( i = 0; i < array1[5]; i++ )

If we assign the increment variable to our array like so

array[i]

then the array is iterated over starting from element 1 and not element 0. Is that right?

#2
When I created the for loop does the i < array[5] in

(Toggle Plain Text)

	for( i = 0; i < array1[5]; i++ )

refer to element 5 in the array, or simply refer to array1 which has 5 elements? From the replies above i'm assuming that it refers to the 6th element in array1. Right?

#3
So if I was to create a proper version of this program, how exactly would I implement this?

Would it be like so:

(Toggle Plain Text)

#include <iostream.h>

int array1[5];
int array2[5];

main()
{
cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n';
cout << "Please enter 5 numbers into this array: ";
cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4];
cout << "and do enter 5 numbers into this array: ";
cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4];

int i;

for( i = 0; i < 6; i++ )
{
if(array1[i] != array2[i]) {
cout << "The array's are not equal" << '\n';
}
cout << "The array's are equal";
}

return(0);
}

I tried the above code and when the arrays are equal it prints the following:

and do enter 5 numbers into this array: 1 2 3 4 5
The array's are equalThe array's are equalThe array's are equalThe array's are equalThe array's are
equalThe array's are not equal

And if the arrays are not equal it prints the following:

Please enter 5 numbers into this array: 1 2 3 4 5
and do enter 5 numbers into this array: 5 4 3 2 1
The array's are not equal

The reason I added the break statement after each cout was to stop the cout repeating itself.

Lol, i'm already getting bad headaches thinking about this!

I just want to thank all of those who have helped me. I really appreciate your help.

And, I want to apologise to all those for posting this corrupt and buggy code.

After all I am a newb

Cheers!

Oct 15th, 2004, 11:18 PM	#4
Mjordan2nd The Supreme Ruler Join Date: May 2004 Location: Houston Posts: 1,476 Rep Power: 6	Actually, my compiler complains when I compress the for loop like that. Don't know why. __________________ "Every gun that is made, every warship launched, every rocket signifies, in the final sense, a theft from those who hunger and are not fed, from those who are cold and are not clothed. The world in arms is not spending money alone. It is spending the sweat of its laborers, the genius of its scientists, the hopes of its children." - Dwight D. Eisenhower

Oct 16th, 2004, 5:11 AM	#6
sys0p Programmer Join Date: Oct 2004 Posts: 73 Rep Power: 5	(Toggle Plain Text) #include <iostream.h> int array1[5]; int array2[5]; main() { cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n'; cout << "Please enter 5 numbers into this array: "; cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4]; cout << "and do enter 5 numbers into this array: "; cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4]; int i; for( i = 0; i < array1[5]; i++ ) { if(array1[i] != array2[i]) { cout << "The array's are not equal" << '\n'; break; } cout << "The array's are equal"; break; } return(0); } #include <iostream.h> int array1[5]; int array2[5]; main() { cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n'; cout << "Please enter 5 numbers into this array: "; cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4]; cout << "and do enter 5 numbers into this array: "; cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4]; int i; for( i = 0; i < array1[5]; i++ ) { if(array1[i] != array2[i]) { cout << "The array's are not equal" << '\n'; break; } cout << "The array's are equal"; break; } return(0); } That should work. I swear the last bit worked for me, but I probably edited it by mistake. Sorry It should work now. I'm using Dev C++ 4 Cheers!

Oct 16th, 2004, 6:34 AM	#8
Ooble I eat cake for breakfast. Join Date: Jul 2004 Location: In my box. Posts: 4,434 Rep Power: 9	You want: (Toggle Plain Text) for (i = 0; i < 6; i++) ... for (i = 0; i < 6; i++) ... You want it to go through 6 times, not until it becomes higher than whatever's in array[5]. __________________ Me :: You :: Them

Oct 16th, 2004, 7:17 AM	#9
mici Programmer Join Date: Oct 2004 Posts: 67 Rep Power: 5	Ooble is right... you've been checking if your iterator is lower than the member no. 5 in your array... by default array[5] is not defined and can be any number until you set it... i.e it can be 4331 or 0 or -234 ... this is why your "for" loop won't work as it should... The probable reason why it ends after 5 loops is that since both array1 and array2 have not been defined and as such are probably bigger positive nums left from some process before the loop finds that they are not equal and breaks there... another thing is that your program shouldn't work at all... if you observe more closely you'll see that the "if" checks if the array1[i] is equal to array2[i] and then if they aren't equal function breaks from the for loop wich is ok, however if they are equal the function also breaks and it never checks for "i" larger than "0". So actualy your program works fine ... it just checks if element 0 from both arrays are equal and displays result and then breaks... Now for the solution you can eather try to repair your code ... remove the breaks and iclude counter for num of equals or !equals... The other solution, much faster and easier to progam is to use memcmp() like this memcmp(array1, array2, 52); 52 is because int takes 2 bytes so if you used chars it would be just 5 and if you used doubles it would be 5*4. memcmp will return 0 if both fields are equal.... Hope this helps a little. __________________ coffee is my heroin.

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Oct 15th, 2004, 3:07 PM	#1
sys0p Programmer Join Date: Oct 2004 Posts: 73 Rep Power: 5	Hi, As I am learning C++ i've decided to post my code to help anyone out there. Of course most of you will be godlike programmers, but for us, the newbs this might help Below is some code to allow the user to input 5 integer numbers into two arrays, array1 and array2. If the numeber's are the same i.e array1 = { 1, 2, 3, 4, 5 }; array2 = { 1, 2, 3, 4, 5 }; Then the message "The array's are equal" is output, else the message "The array's are not equal" is output. (Toggle Plain Text) #include <iostream.h> int array1[5]; int array2[5]; main() { cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n'; cout << "Please enter 5 numbers into this array: "; cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4]; cout << "and do enter 5 numbers into this array: "; cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4]; int i; for( i = 0; i < array1[5]; i++ ) { if(array1[i] != array2[i]) { cout << "The array's are not equal" << '\n'; break; } cout << "The array's are equal"; } return(0); } #include <iostream.h> int array1[5]; int array2[5]; main() { cout << "This program determines if the number's you enter into array 1 and array2 are identical" << '\n'; cout << "Please enter 5 numbers into this array: "; cin >> array1[0] >> array1[1] >> array1[2] >> array1[3] >> array1[4]; cout << "and do enter 5 numbers into this array: "; cin >> array2[0] >> array2[1] >> array2[2] >> array2[3] >> array2[4]; int i; for( i = 0; i < array1[5]; i++ ) { if(array1[i] != array2[i]) { cout << "The array's are not equal" << '\n'; break; } cout << "The array's are equal"; } return(0); } If there are any mistakes here please point them out. After all the purpose of this code is to help us learn Oh, maybe some suggestions as how to improve the program. One would be to say: if size of array1 is not equal to size of array2, then break. Obviously. But I haven't implemented it in the code yet. Cheers!

Oct 15th, 2004, 3:25 PM	#2
kilgayne Newbie Join Date: Oct 2004 Location: Quebec Posts: 10 Rep Power: 0	iostream.h sucks conio.h rulez \o/ (Toggle Plain Text) cprintf("I guess this could eventually help n00bs.\r\nDon't give up!"); cprintf("I guess this could eventually help n00bs.\r\nDon't give up!"); __________________ yeah, i suck ^^; Quote from Bill Gates : "If you can't make it good, make it looks good."

Oct 15th, 2004, 11:00 PM	#3
Das Bruce Newbie Join Date: Oct 2004 Posts: 10 Rep Power: 0	I'm not sure if these are errors but you might want to look into it. (Toggle Plain Text) for( i = 0; i < array1[5]; i++ ) for( i = 0; i < array1[5]; i++ ) array1[5] is actually the 6th element. (Toggle Plain Text) int i; for( i = 0; int i; for( i = 0; could be compressed into (Toggle Plain Text) for(int i=0; for(int i=0;

Oct 16th, 2004, 12:46 AM	#5
Das Bruce Newbie Join Date: Oct 2004 Posts: 10 Rep Power: 0	What are you using? I use DevC++ which comes with gcc. DevC++ home

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