code:

// This example will work with any PIC18 because of this header
#include <p18cxxx.h>

void main()
{
    PORTA = 0xff; // Write 0xff to PORTA, making all pins outputs high

    TRISA = 0x00; // Write 0x00 to TRISA, setting all PORTA pins to outputs

    LATAbits.RA4 = 0; // Clear the RA4 bit of PORTA (Use LATA rather than PORTA for read/modify/write operations)
    LATA &= 0xfe; // The C18 compiler is smart enough to turn this into a bit clear instruction

    // Infinite loop - returning from main actually resets the PIC so you don't usually want that to happen
    while(1);
}