printf("hello world");
//The text hello world is placed in program memory and never changes.
x = 'B' ;
//The letter 'B' is permanently set in program memory.

cons char c = 57 ;

int num_val ; //declare an integer variable 
//declare an enumeration
enum { zero_val , one_val , two_val , three_val ) ; 
num_val = two_val ; // the same as : num_val = 2 ;

enum { start=10 , next1 , next2 , end_val } ; 

…
…
enum { red_led_on = 1 , green_led_on, both_leds_on } ;
#define leds PORTB
…
…
PORTB = 0x1 ; // means turn the red LED on
leds = red_led_on ; // means the same thing

#include <16F877.h>                         //register definition header file for
#fuses HS,NOWDT                           //a Microchip PIC16F877 and fuses 
unsigned  char z ;                               // declare z 
void main (void) 
{
set_tris_d(0x00);                   //set all bits of port D for output 
           set_tris_b(0Xff);                    //set port B for all input
           while(1)
           {
z = input_b( ) ;           // read the binary value on the 
//port B pins ( i.e., input from port B)  
output_d(z+1) ;          // write the binary value read from B
// plus 1 to port D
           }
}

set_tris_b(0xc3);       //set the upper 2 and lower 2 bits of 
//port B for input , the rest for output
//0xc3=0b11000011

dog = 35 ; 
val = dog ; 
dog = dog + 0x35 ; 
val = (2 * ( dog + 0172 ) ) + 6 ; 
y = ( m * x ) + b ;

y= m * x + b ;

y = ( m * x  ) + b ;

#include <16F877.h>             //register definition header file for
#fuses HS,NOWDT                           //a Microchip PIC16F877 and fuses

unsigned char z ; //declare z 

void main(void) 
{
            port_b_pullups(TRUE);
            set_tris_d(0x00);                               //set all bits of port D for all output
            set_tris_b(0xFF);                               //set port B for all input

            while(TRUE)
            {
                z = input_b( ) & 0x6 ;                    //read the binary value on 
//the port B pins ANDed with 00000110
output_d(input_d( )  |  0x60 );        // write the binary value from (port D
                                                //ORed with 01100000) back to port D 
output_d(input_d( )  & 0xFE) ;     //write the binary value from( port D 
                                                                        //ANDed with 0xFE) to port  D .
            }
} 

input_b( ) & 0x6
same as
PORTB & 0x06
same as
PORTB & 0b00000110 // RB0,RB3,RB4,RB5,RB6,RB7 always zeros (mask)

output_d(input_d( )  |  0x60 );//0bxxxxxxxx | 0b01100000 = 0b0xx00000
سطر الإخراج الثانى يبين طريقة إجبار بت من المنفذ للحالة المنخفضة عن طريق عملية AND(&) للبت مع الصفر .
output_d(input_d( )  & 0xFE) ;//0bxxxxxxxx & 0b11111110 =0bxxxxxxx0