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Sid2286
Joined: 12 Aug 2010
Posts: 119
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| Accessing Array |
 Posted: Thu Jan 02, 2014 4:49 am |
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I want to access an array and display on the LCD but getting the following error.
ERROR: previous identifier must be a pointer
how do I change my following code:?
| Code: |
#include <18F4520.h>
#device ICD=TRUE ADC=10
#fuses HS,NOLVP //,WDT128
#use delay (clock=8MHZ)
#include <flex_lcd.c>
#include <button.c>
const char* my_lib[]={"abc", "xyz", "123","ABCD"};
int8 B7 = 0; // Enter Button->B0
int8 B5 = 0; //right shift Button->B5
int8 B6 = 0; //increment Button->B6
int my_lib()
{
int* x;
while(true)
{
if(button(PIN_B6, 0, 50, 10, B6, 1))
break;
}
while(true)
{
printf(lcd_putc,"\n %c ",my_lib[x]);
delay_ms(1000);
if(button(PIN_B6, 0, 50, 10, B6, 1)) //Increment value
x++;
if(x==3)
x=0;
if(button(PIN_B7, 0, 50, 10, B7, 1)) // Enter Pressed Return Value
{
return x;
delay_ms(500);
}
}
}
void main()
{
int x;
PORT_B_PULLUPS(true);
while(True)
{
if(button(PIN_B7, 0, 50, 10, B7, 1))
{
printf(lcd_putc," \fUnits\nto Display");
delay_ms(1000);
x =my_lib();
}
printf(lcd_putc,"\n %c ",my_lib[x]);
delay_ms(1000);
}
} |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19539
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| Posted: Thu Jan 02, 2014 5:51 am |
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Several things worthy of comment. Some CCS specific, and other just 'wrong'....
First, either get rid of the const keyword, or do a search here on 'pointer to constant'. In the PIC, ROM, and RAM are completely separate memory spaces. Hence a standard 'pointer', which points to RAM, can't be used to access a 'const' (stored in ROM) variable. There are ways of doing this (#DEVICE PASS_STRINGS=IN_RAM), or using the 'rom' construct, rather than 'const', which adds extra code to allow pointers to be constructed.
Then it is really bad programming practice to use the same name for a function and a variable. Avoid this. This is probably what actually gives the error.
Then though the basic construction is wrong. mylib[x] is a pointer to an array of characters, not a character, which '%c' expects....
Then you declare a pointer 'x', but nowhere do you initialise it. It could be pointing anywhere!. Then you declare x as a pointer, but the function returns an integer. |
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