Array Problem....

[Emo]

Ok, I'm learning arrays and I pretty much have the concept of them and how they work.. now my problem is that I dont get how to store things in them...

anyway, I've been working on this problem i'm given and it doesnt look too good:

#include <stdio.h>
#define GRADES 10

main()

{

    int Ngrades[GRADES] = {0}, i, loop = 1;
    float total, avg;


    while (loop == 1) {
            printf("Please enter %d grades\n", GRADES);
        for (i=0; i<10; i++) {
            scanf("%d", &Ngrades[i]);
        
            printf("Calculating......");
            for (i=0; i<10; i++) {
                total += Ngrades[GRADES];
            }
        
        avg = (float) total/(Ngrades[GRADES]);

            printf("The %d numbers entered were: \n", GRADES);
            
        for (i=0; i<10; i++) {
            printf("Ngrades[%d] = %d\n", i, Ngrades[i]);
        }

        printf("\n");

        printf("the avg of the %d numbers was: %.1f\n", GRADES, avg);
        
        
        }

            
        }

        return 0;

} 

now.. for some reason, instead of putting the 10 numbers in one array (one demention) it puts each number in a new array....

what I need it to do is get the 10 grades from ther user, display those 10 numbers, then take the average of all of them...

then there are other things like calculating the letter grade based on teh average but for now I want to get this straight

thanks for any help!
-Emo

[CornedBee]

??? In the average calculation:
(Ngrades[GRADES])

I think you mean
GRADES

Also your for-loops should use GRADES as the upper bound.


And

now.. for some reason, instead of putting the 10 numbers in one array (one demention) it puts each number in a new array....

:***:
You only have one array...

[Emo]

Originally posted by CornedBee
:***:
You only have one array...

ok but then why do I get this output:

[quote]
Please enter 10 grades
98 45 88 66 52 65 78 87 65 95
Calculating......The 10 numbers entered w
Ngrades[0] = 98
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -76.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 45
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -66.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 88
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -56.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 66
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -46.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 52
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -36.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 65
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -26.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 78
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -16.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 87
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: -6.2
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 65
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: 3.8
Please enter 10 grades
Calculating......The 10 numbers entered w
Ngrades[0] = 95
Ngrades[1] = 0
Ngrades[2] = 0
Ngrades[3] = 0
Ngrades[4] = 0
Ngrades[5] = 0
Ngrades[6] = 0
Ngrades[7] = 0
Ngrades[8] = 0
Ngrades[9] = 0

the avg of the 10 numbers was: 13.8
Please enter 10 grades

[quote]

[CornedBee]

!!!!

Let me test that...

[CornedBee]

if only you had proper indentation...

#include <stdio.h>
#define GRADES 10

int main()
{
	int Ngrades[GRADES] = {0}, i, loop = 1;
	float total, avg;

	while (loop == 1)
	{
		printf("Please enter %d grades\n", GRADES);

		for (i=0; i<GRADES; i++)
		{
			scanf("%d", &Ngrades[i]);

			printf("Calculating......");

			for (i=0; i<GRADES; i++)
			{
				total += Ngrades[GRADES];
			}

			avg = (float) total/(float)GRADES;

			printf("The %d numbers entered were: \n", GRADES);

			for (i=0; i<GRADES; i++)
			{
				printf("Ngrades[%d] = %d\n", i, Ngrades[i]);
			}

			printf("\n");
			printf("the avg of the %d numbers was: %.1f\n", GRADES, avg);
		}
	}
	return 0;
}

You should now be able to find the error yourself.

[Emo]

it's something in the last for loop... hmmm...

dont tell me!!

lets see..

for (i=0; i<GRADES; i++)
{
printf("Ngrades[%d] = %d\n", i, Ngrades[i]);
}

if I replace teh i<GRADES to 1, it gets rid of the un-needed lines but it's not displaying my numbers right...

maybe in the Ngrades[i]; ...

ok.. I'll keep trying...

thanks for all the help so far.... and by the way, sorry, I havn't indented a lot so I dotn know how to do it correctly..

-Emo

[CornedBee]

A hint: the problem lies not in a single for-loop but rather in the way they act together.

[Emo]

Ok I finally got some work done...

I fixed the array and right now it looks something like:

Please enter 10 grades
15 16 18 17 54 68 48 85 16 98
The 10 numbers entered were:
Ngrades[0] = 15
Ngrades[1] = 16
Ngrades[2] = 18
Ngrades[3] = 17
Ngrades[4] = 54
Ngrades[5] = 68
Ngrades[6] = 48
Ngrades[7] = 85
Ngrades[8] = 16
Ngrades[9] = 98
Calculating......

the avg of the 10 numbers was: -10737374.0
Please enter 10 grades

so all I have left is the avg to be fixed and then the letter grades according to the avg...

Thanks for the help so far guys!

-Emo

[Jop]

Take a really close look at this part:

			for (i=0; i<GRADES; i++)
			{
				total += Ngrades[GRADES];
			}

hehe can happen mate

[Emo]

w0000t I'm on a roll tonight

jsut got the avg to work right... but does anybody remember how to use the fflush() command because I need to clear out the buffer after each use.. or the avg keeps adding the old one..

-Emo

[Emo]

Originally posted by Jop
Take a really close look at this part:

			for (i=0; i<GRADES; i++)
			{
				total += Ngrades[GRADES];
			}

hehe can happen mate

Yeah I figured it out..thanks! I had to set total to 0 then I modified it to this:

for (i=0; i<GRADES; i++)
{
total = total += Ngrades[i];
}

-Emo

[Jop]

total = total += Ngrades[i];

hmm that should either be:

total = total + nGrades[i];

or

total += nGrades[i];

x += y ;

actually is read by the compiler as

x = x + y;

[CornedBee]

But actually
total = total += Ngrades[i];
will work too, although it's confusing and an unnecessary assignment. It's equivalent to writing
total += Ngrades[i];
total = total;
which undoubtly works

[Emo]

well it works and I'm happy with that.... now can anybody help me with the fflush?

thanks
-Emo

[Jop]

This is what MSDN says about it:

fflushSee Also
Stream I/O Routines | fclose | _flushall | setvbuf
Requirements
Function Required header Compatibility 
fflush <stdio.h> ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP 

For additional compatibility information, see Compatibility in the Introduction.

Libraries

All versions of the C run-time libraries.
Flushes a stream.

int fflush( 
   FILE *stream 
);
Parameter
stream 
Pointer to FILE structure. 
Return Value
fflush returns 0 if the buffer was successfully flushed. The value 0 is also returned in cases in which the specified stream has no buffer or is open for reading only. A return value of EOF indicates an error.

Note   If fflush returns EOF, data may have been lost due to a write failure. When setting up a critical error handler, it is safest to turn buffering off with the setvbuf function or to use low-level I/O routines such as _open, _close, and _write instead of the stream I/O functions.

It expects a stream, and since you're using the keyboard in this case (actually you're using the standard input stream) you should pass it the stdin (Standard Input Stream)

fflush (stdin);

[Emo]

Thanks!

-Emo