Thread: Small error in C implementing fCfS algo

I m trying to implement fCfS Algo.
The programm is not ful fledged complete.
But the programm ends abruptly after the first input

So pls can anyone help me whats wrong ?

Code:

#include <stdio.h>
#include <conio.h>
int nopr,art[50],jt[50],start,wt[50],i,j,k,l,m;
void fcfs ()
{
	//int i,j,k,l,art[50],jt[50],start,wt[50];
	printf ("\n Enter arrival Time in ascending order\n");
	for (i=0;i<=nopr;i++)
	{
		scanf ("%d", art[i]);
	}
	printf ("\n Enter job Time\n");
	for (j=0;j<=nopr;j++)
	{
		scanf ("%d", jt[j]);
	}
	for (k=1;k<=nopr;k++)
	{
		start=art[i]+jt[j];
		wt[l]=start-art[i];
	}
	printf ("fCfS Algo");
	printf ("The waiting Time for each process is :\n");
	for (m=0;m<=nopr;m++)
	{
		printf ("%d",wt[l]);
	}

}
void main ()
{
	//int nopr,art[50],jt[50],start,wt[50],i,j,k,l;
	printf  ("\n\n------------- Scheduling Algorithm fCfS -------------\n\n");
	printf ("Enter no of process \n");
	scanf ("%d\n",&nopr);
	fcfs ();
}

Originally Posted by ledow

What value do you read in in the first loop and where do you put it?

HINT: TURN ON YOUR DAMN COMPILER WARNINGS.

i Dont know how to turn on the compiler warning.
i m using MinGW Compiler.

What value are u talking about.
See this is the image where the error occurs

Originally Posted by grumpy

Addresses need to be passed to scanf(), not values. You need to add ampersands. Without those ampersands, your scanf() calls in fcfs() are writing to random areas of memory.

Also a loop of the form for (i = 0; i <= nopr; i++) loops nopr+1 times.

And claudiu is right: main() returns int, not void.

yea i know i need to add ampersands in scanf.
But do i need to do taht in arrays too ?
'coz i have learnt that in arrays it directly points to addres so no need to add ampersands.

& so can u pls tell me whats the correct loop ?

& i have corrected that 'coz my compiler always gives error with void in main to change to int().
Can u pls explain me that part, i dont seem to understand it

Originally Posted by ledow

See the bit where you typed in "gcc fCfs.C -o fCfS"? Put a -Wall into it:

Code:

gcc -Wall -Werror fCfs.C -o fCfS

would be my recommendation.

Then fix everything it tells you about.

hey thanks man
But now its telling me this :

int & int are same so why error ?

Cross-posted here, here, and here.

Thanks People Just by adding an ampersand "&", it solved the issue.
But in arrays it directly points to the address, so there is no need to add an ampersand, RIGHT ???
So why this error ?

Originally Posted by grumpy

Also a loop of the form for (i = 0; i <= nopr; i++) loops nopr+1 times.

Hey thanks.
Figured it out.
Removed teh equal sign.

Originally Posted by ledow

I advise you to read up on arrays better, because you're getting confused. Assuming:

Code:

int array[10]

Then "array" is equivalent to &array[0], yes. But array[0] is "the contents of array box 0", if you like. The square brackets ([]) are reaching into memory for you and retrieving the contents of the array. You *could* do it yourself (e.g. array + some offset) but the [] do the job for you. You CAN have arrays of pointers, too, but this ISN'T one. It's an array of int's. So the 0th element of the array is an int. When you say "array[0]", it's going to be an int. If you want a pointer to that int, the most convenient way is to use "&array[0]".

However, the array as a whole COULD be referred to using a pointer (&array[0]) which is sometimes "shortcut" to something simpler (array) for convenience. Pointers and arrays are linked (all arrays are stored in contiguous memory and referred to by a pointer) but not in the way you think.

Don't spend your C programming life just putting an * or & where you think things should be pointers or where you get compiler errors. Think about what they mean and what you're actually storing and referring to. Otherwise, the first time you run into something complex, you'll mess it up (e.g. I wrote a qsort comparator function lately that puts NULL pointers before others - if you don't THINK about what all the *'s and &'s mean, you mess it up. As it was, I got it to work first-time by thinking about what I wanted - and even commented the code on that fact, I was so shocked!).

Thanks man
to get much more insight in C, what do u think what should i refer too ?
& where would i get some practice programms ?

i have ANSI C by Ritchie, what do u think any other refernces ?