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cchappyboy
Joined: 03 Dec 2008
Posts: 45
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| Something about pointer in CCS C |
 Posted: Thu Nov 19, 2009 9:58 am |
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I made a two-dimensional array
| Code: |
char comm[4][6]={"How are you?","I am fine.","Thank you!","You are welcome!"}
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and a pointer variable int *p;
How can I give the first address of comm[0][0] to p ?
I try make *p=comm[0][0] or p=&comm[0][0] but it does not work.
I heard about some of C can use int (*p)[4] as a pointer of two-dimensional array, but it looks CCS C doesn't do that.
Please give me some idea about this.
Any concern I appreciate in advance. Thanks. |
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Kamputty
Guest
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| Posted: Thu Nov 19, 2009 11:12 am |
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Here is a working example...
Notice the "char *p"...
You need a pointer to a char, not a pointer to an "int"...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
#include <stdio.h>
int main (int argc, char *argv[])
{
char comm[][50]={"How are you?","I am fine.","Thank you!","You are welcome!"};
char *p;
int x;
for(x=0; x<4; x++)
{
p=comm[x];
printf("The message is [%s]\n", p);
}
return(0);
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Nov 19, 2009 2:40 pm |
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To Kamputty:
| Quote: |
#include <stdio.h>
int main (int argc, char *argv[])
{
char comm[][50]={"How are you?","I am fine.","Thank you!","You are welcome!"};
char *p;
int x;
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Your code doesn't compile in CCS (PCH vs. 4.099). Also, CCS doesn't
support argc or argv. You can't "return" from main(). There is no O/S
to return to.
-------------------------------------------------------
To cchappyboy:
Here is an example of how to get a pointer to individual elements
in a two dimensional text array. The program below has the
following output:
| Quote: |
Sunday
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Last Test: Wednesday
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| Code: |
#include <18F452.h>
#fuses XT,NOWDT,PUT,BROWNOUT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, ERRORS)
char weekday_names[7][10] =
{
{"Sunday"},
{"Monday"},
{"Tuesday"},
{"Wednesday"},
{"Thursday"},
{"Friday"},
{"Saturday"}
};
void display_text(char *ptr)
{
printf("%s \r", ptr);
}
//======================================
void main ()
{
int8 i;
char *p;
// Pass a pointer to each array element.
// Display all of them.
for(i=0; i < 7; i++)
{
display_text(weekday_names[i]);
}
// Get a pointer to one element in the array.
// Display it.
i = 3;
p = weekday_names[i];
printf("Last Test: %s", p);
while(1);
}
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This was tested with PCH vs. 4.099. |
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cchappyboy
Joined: 03 Dec 2008
Posts: 45
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| Posted: Thu Nov 19, 2009 4:59 pm |
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Thanks for you guys' help.
My ccs version is 4.066
This time I try this:
| Code: |
char comm[4][20]={"How are you?","I am fine.","Thank you!","You are welcome!"};
char *p;
p=comm[0];
printf("%s", p);
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Pass the build procedure but it don't work.
But works at
| Code: |
printf("%s",comm[0]);
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What is the problem? Thanks. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Thu Nov 19, 2009 5:49 pm |
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| Post your PIC. Always do this. |
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