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Ark2040
Joined: 22 Jul 2014
Posts: 3
Location: N/A
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| Silly parameters function problem |
 Posted: Tue Jul 22, 2014 3:16 pm |
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Hi guys, I would like to do any like this code, but I dont know why doesnt work ?
| Code: |
#include <16f877.h>
#fuses HS,NOWDT,NOPROTECT
#use delay (clock=4000000)
#byte PORTA=0x05
#byte PORTB=0x06
#byte PORTC=0x07
#byte PORTD=0x08
int z;
void main()
{
//set_tris_a(0b00011111);
set_tris_b(0b11111111);
set_tris_c(0b11111111);
set_tris_d(0b00000000);
function(5,2);
PORTD=z;
}
void function(int x, int y){ // IT MUST RECOGNIZE NUMBERS WRITTEN UP
z=x*y;
return
} |
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newguy
Joined: 24 Jun 2004
Posts: 1911
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| Posted: Tue Jul 22, 2014 3:24 pm |
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Either
| Code: | int8 z;
z = x * y;
return z;
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Or
First method will definitely work; 2nd may make the compiler complain. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Jul 22, 2014 3:27 pm |
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This is a basic C question. You need to study this topic off the forum.
Google for it:
| Quote: | | How to return a value from a function in C |
Look at some of the hits that you get. Study how they do it.
http://www.macs.hw.ac.uk/~pjbk/pathways/cpp1/node162.html |
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temtronic
Joined: 01 Jul 2010
Posts: 9270
Location: Greensville,Ontario
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| Posted: Tue Jul 22, 2014 3:30 pm |
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if making a function, then it can't be 'void', must be an int as well...
it's covered in the help files...or see any number of the example programs CCS kindly supplies...
hth
jay |
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Ark2040
Joined: 22 Jul 2014
Posts: 3
Location: N/A
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| Thk U |
| Posted: Tue Jul 22, 2014 4:52 pm |
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| newguy wrote: | Either
| Code: | int8 z;
z = x * y;
return z;
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Or
First method will definitely work; 2nd may make the compiler complain. |
Yes, I knew that Newguy, but I'm trying to write inside parentheses to obtain a result so ... I can not to do that  |
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Ark2040
Joined: 22 Jul 2014
Posts: 3
Location: N/A
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| Posted: Tue Jul 22, 2014 5:55 pm |
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HEY PCM PROGRAMMER I GOT IT THKS U
#include <16f877.h>
#fuses HS,NOWDT,NOPROTECT
#use delay (clock=4000000)
#byte PORTA=0x05
#byte PORTB=0x06
#byte PORTC=0x07
#byte PORTD=0x08
int8 z;
void function(int8 one, int8 two)
{
z=one+two;
}
void main()
{
//set_tris_a(0b00011111);
set_tris_b(0b11111111);
set_tris_c(0b11111111);
set_tris_d(0b00000000);
function(2,3);
PORTD=z;
} |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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| Posted: Wed Jul 23, 2014 8:20 am |
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It works but is very ugly code.
General rule is: Use as few global variables as possible.
In a small program like this it isn't a big problem but in a larger problem you will loose the overview of all the places where a variable is used and changed.
Why do you not want to have the function return a value? | Quote: | | but I'm trying to write inside parentheses to obtain a result so ... I can not to do that |
This suggests your teacher wanted you to learn about macro's and that's not what you have created here... |
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