sleep( ) ;                     // this function performs a 1 second delay ,
// with no parameters, in or out

 
printf("this is a parameter  %d" , x ) ; 
// printf will print its parameters
 
c = getchar( ) ;           // getchar will return a value from the 
// standard input

type function_name( type param1 , type param2 , …)
{
           statement1 ;
           statement2 ;
           ………….. 
statementx ;
}

unsigned  char getchar(void)
{
           while ( ( PIR & 0x20) == 0 )
                       ;                                   // wait for character to arrive 
           return RCREG ;                    // return its unsigned char value to the caller
}

// declarations of global variables would be firs      
int var1 , var2 , var3 ;
// declarations of functions would come next 
int  function1( int x , int y)
}
}
void function2(void)
{
}
// main would be built last
void main(void)
{
            var3 = function1(var1 , var2);
}

int var1 , var2 , var3 ;                       // declaration of global variable 
void main(void)                                  // main
{
// these functions are not yet known to the compiler
            var3 = function1(var1,var2);
            function2( ) ;
}
// declarations of functions here now generate a 
// "Function Redefined Error"
int function1( int x , int y )
{
}

void  function2 ( void)
{
}

// the prototype of function tells compiler what to expect 
int function1(int  , int ) ;
int function2(void) ;
int var1 , var2 , var3 ;                       // declaration of global variables 

void main(void)                                  //main
{
            var3 = function(var1 , var2 );
            function2( ) ;
}
// the declaration of the functions here is 
// perfectly OK , because
//the format of the functions is presented in the prototypes

int function1(int x , y )
{
}

void function2(void)
{
}

int  z ;                                                 // global variable z
void sum(int x , int y)
{
            z = z + y ;                   // z is modified by the function , sum( ) 
}

void  sum(int x , int y) 
{
            return ;                       // this would return nothing ..
            z = x + y ;                   // and this would be skipped
}

float cube(float v ) 
{
            return (v * v * v);      // this returns a type float value
}

void main(void)
{
            float a ;
            b = 3.14159 ;              // put PI into b 
            a = cube(b) ;               // pass b to cubed function , and 
// assign its return value to a 
            printf("a =  %f , b =  %f \n" , a , b ) ; // print the result
            while(1)                      // done
                        ;
} 

char *p ;         // p is a pointer to character
int *fp ;           // fp is a pointer to an integer  

char *p ;         // p is a pointer to a character 
char a , b ;      // a and b are characters 
p = &a ;          // p is now pointing to a

b = *p ;                       // b equals the contents pointed by p

b = a ; 

char  *p ;                    // p is a point to a character
char a , b;                   // a and b are characters 

 
p = &a ;
 
*p = b ;                       // the location pointed by p , is 
// assigned the value of b

a = b ; 

 
كلما قرأت هذه العوامل , حاول أن تقرؤها كما يلى : " b تعين القيمة المشار إليها بواسطة p " و " p تعين عنوان a " . هذا يساعد على تجنب معظم الأخطاء الشائعة مع المؤشرات :
 
b = p ;             // b will be assigned a value of p , an address , 
// not what p point to 
 
p = a ;                         // p will be assigned the value of a , not its address .

unsigned char *my_port;                   // declare my_port as pointer 
my_port = 0x1010 ;                           //assign my_port with address value
*my_port = 0xaa ;                             // now assign my_port's address a value

int digits[10] ; // this declares an array of 10 integer
char str[20] ;              // this declares an array of 20 characters

str[0] , str[1] , str[2] , ………………str[19]

int  array[5] = {12 , 15 , 27 , 56 , 94 } ;

char digits[10] = {0,1,2,3,4,5,6,7,8,9};          // an array of characters
num = digits[12] ;                                           // this reads outside the array .

char  str[12] ;                                     // variable string
printf("Hello World") ;                     // constant string in program memory 
const cstr[16] = "Constant String" ;
// constant string in program memory

char stng[20] ;
char *p ;

p = stng ;                    // p is pointing to stng[0]

p = &stng[0] ;            // p is pointing to stng[0]

#include <16F877.h> //register definition file for 
#fuses HS,NOWDT               //a Microchip PIC16F877
#use delay(clock=10000000 //setup the RS232 port for standard output
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,stream=RS232,bits=8)
#include <stdio>

const char  s[15] = {"This is a test") ;
char i ;
char *p ; 
void main(void) 
{
            for(i=0;i<15;i++)                    // print each character of the array
                        putchar(s[i]) ;             // by using I as index
            p = s ;                                      // point to string as whole 
            for(i = 0 ; i<15 ; i++ )             // print each character of array
                        putchar(*p++);           // and move to the next element 
                                                            // by incrementing the pointer p 
            while(1)
                        ;
}