#include <stdio.h>

void print_hex( int input );

int main( int argc, char** argv ){

	int input;
	
	printf( "input number: " );
	scanf( " %d", &input );
	
	/* print hex with printf */
	printf( "%x\n", input );

	/* print hex with my function */
	print_hex( input );

	return 0;

}

/* print input in hex */
void print_hex( int input ){

	int var, i;
	int len = 0;

	char buf[255];

	do {
		var = input % 16;
		input /= 16;

		/* try to convert ascii code */
		if( var < 10 )
			buf[len] = var+48;
		else
			buf[len] = var+55;

		len++;

	} while( input > 0 ); /* bigger than 16? then try again */

	/* print reversely */
	for ( i = len ; i > 0 ; i-- )
		putchar( buf[i-1] );
	
	putchar( '\n' );

}