مثال های برنامه نویسی به زبان c

- مثال ۱:برنامه ای که شکل زیر را به خروجی ببرد:

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main ()

{ 

int i,j;

for (i = 1; i <=5; i++)
   {
   for (j = 1; j <=i; j++)
      {
      printf("*");
      }
   printf ("\n");
   }
}

- مثال ۲:برنامه اعداد اول:

/******************************************************/
/*                                                    */
/* Prime Number Sieve                                 */
/*                                                    */
/******************************************************/

#include 

#define SIZE     5000
#define DELETED     0

/*******************************************************/
/* Level 0                                             */
/*******************************************************/

main ()

{ short sieve[SIZE];

printf ("Eratosthenes Sieve \n\n");

FillSeive(sieve);
SortPrimes(sieve);
PrintPrimes(sieve);
}

/*********************************************************/
/* Level 1                                               */
/*********************************************************/

FillSeive (sieve)               /* Fill with integers */

short sieve[SIZE];

{ short i;

for (i = 2; i < SIZE; i++)
   {
   sieve[i] = i;
   }
}

/**********************************************************/

SortPrimes (sieve)                /* Delete non primes */

short sieve[SIZE];

{ short i;

for (i = 2; i < SIZE; i++)
   {
   if (sieve[i] == DELETED)
      {
      continue;
      }
   DeleteMultiplesOf(i,sieve);
   }
}

/***********************************************************/

PrintPrimes (sieve)                  /* Print out array */

short sieve[SIZE];

{ short i;

for (i = 2; i < SIZE; i++)
   {
   if (sieve[i] == DELETED)
      {
      continue;
      }
   else
      {
      printf ("%5d",sieve[i]);
      }
   }
}

/***********************************************************/
/* Level 2                                                 */
/***********************************************************/

DeleteMultiplesOf (i,sieve)   /* Delete.. of an integer */

short i,sieve[SIZE];

{ short j, mult = 2;

for (j = i*2; j < SIZE; j = i * (mult++))
   {
   sieve[j] = DELETED;
   }
}

                      /* end */

- مثال ۴ :مثالی خیلی ساده از کاربرد switch

#include 

int main (void)
{
char ch;
printf ("\nEnter Character A,B or C: ");
ch = getchar ();

switch (ch)
 {
  case 'A' : printf ("You Entered A");
             break;
  case 'B' : printf ("You Entered B");
             break;
  case 'C' : printf ("You Entered C");
             break;
  default : printf ("You Didnot Entered A, B or C");

  }
return 0;
}

در اینجا مثالی ساده از کاربرد   if را در برنامه نویسی مشاهده می کنید:

The following program uses an if statement to validate the users input to be in the range 1-10.

	#include 

	main()
	{
		int number;
		int valid = 0;

		while( valid == 0 ) {
			printf("Enter a number between 1 and 10 -->");
			scanf("%d", &number);
			/* assume number is valid */
			valid = 1;
			if( number < 1 ) {
				printf("Number is below 1. Please re-enter\n");
				valid = 0;
			}
			if( number > 10 ) {
				printf("Number is above 10. Please re-enter\n");
				valid = 0;
			}
		}
		printf("The number is %d\n", number );
	}


	Sample Program Output
	Enter a number between 1 and 10 --> -78
	Number is below 1. Please re-enter
	Enter a number between 1 and 10 --> 4
	The number is 4