C Code Anyone?

[planecrazy.eu]

Hey...

Ages ago i asked for some help on some c code on here, and got a good response, well i got the answer. I now find my self stuck.

I am trying to make some code, using loops, that can figure out all possibilities for a value of numbers.

IE if i enter 5, then there is 1..2, 1..3, 1..4, 1..5, 2..3, 2..4, 2..5, 3..4, 3..5, 4..5,

I then need to read this info in to some sort of array, however, i cant figure the above. i can get them, but i end up with 1..1, 2..2, 3..3, etc.

Using loop with nested loop.

thanks

[under_exposed]

I do like C

#include <stdio.h>

void main (int argc, char * argv[])
{
int i,j;
int requested_value;

if (argc != 2)
{
printf( "\nUsage: %s value ", argv[0] );
return;
}

requested_value = atoi(argv[1]);

if (requested_value > 1)
{
for (i=1;i<=requested_value;i++)
{
for (j=i+1;j <= requested_value;j++)
{
printf("%d..%d, ",i,j);
}
}
printf("\n");
}
else
{
printf("no range\n");
}


}

(Why are leading spaces removed from posts?)

[planecrazy.eu]

Thanks for that =)

You dont by any chance know how to inverse a matrix or array do you?

[under_exposed]

What do you mean by inverse a matrix or array?

[bnt]

Originally Posted by under_exposed

(Why are leading spaces removed from posts?)

On other forums you'd have CODE tags for this purpose, but since they don't work here, you can get the general idea across by using the Indent buttons like this:

#include <stdio.h>

void main (int argc, char * argv[])
{

int i,j;
int requested_value;

if (argc != 2)
{

printf( "\nUsage: %s value ", argv[0] );
return;

}

...

[cdtaylor_nats]

There is a matrix inversion algorithm here

http://www.thescripts.com/forum/thread513120.html

[planecrazy.eu]

Thats just what i need....

I have another problem now...

The code is similar

for(i=1;i<=number;i++)

{

for(j=i+1;j<=number;j++);
{
e = j + c^2

}
}

What i need to do is get the value for e, then on the next loop add the new e value to the old e value to sum up?

Any ideas?

Code is an example, so might be a little not to the point.

[under_exposed]

like this?

e = 0;
for(i=1;i<=number;i++)

{

for(j=i+1;j<=number;j++);
{
e += j + c^2

}
}

[tallsandwich]

Buy this book

If you enjoy C, get this:

Title: "Expert C Programming"
Author: "Peter van der Linden"

I coded C for years and then read this book and at that stage I found it easy to read, interesting, both entry level AND expert level too. The guy ran the Sun "C" Compiler team and then later was a key player in the Java project.

It explains all the quirks of the language, common pitfalls and it is not a doorstop. I can't recommend it enough, it' actually enjoyable and explains all the WTFs you get in a succinct way.

P.S. It's orange with a blue fish on the front.

[planecrazy.eu]

Thanks for the book advice, i will see if i can hunt a copy down...

I am stuck on one more thing...

My app calculates numbers, some are + and some are -. I need to some how strip the - figures and just make them +, as what i want to do is add them togeather. If it was a - and a - it would be ok, but i have mixed numbers and need to add them all together in a non matchmatical way of plus and minus powers.

Ie

I want -4,5,-2 and 4 to add up to 15.

Any help is appreciated.

[Saab Dastard]

Square them, then get the square root - that should make 'em all positive!

I'll get me coat...

SD

[matt_hooks]

Saab, that's exactly what I would have suggested. Square all numbers then square root them, unless there's a specific function to ignore signs in C, long time since I've done any C programming.

[bnt]

I think you're after an "absolute value" function, called abs(int x) or fabs(double x), or something like that? You'd apply it to each value before summing them. I found this code example that shows how they're used.