10進数を16進数に変換する方法

/*
 *   ：           16  
 */

#include <stdio.h>
#include <stdlib.h>

void hex_covert(int x);

void hex_covert(int x)
{
	char a;
	int y;
	if (x==0)
	{
		printf("0");
		return ;
	}

	y = x%16;
	if (y>=10)
		a = (y - 10) + 'a';
	else
		a = y + '0';
	x = x/16;
	if (x != 0)
		hex_covert(x);
	
	printf("%c", a);
}

int main()
{
	int x;

	printf("

===========Program Start==============
");
	printf("Please input a number to covert:");
	scanf("%d", &x);
	printf("Hex:%x

", x);

	printf("Now, let's use a function to covert
");
	printf("Hex:");
	hex_covert(x);
	printf("
");
	printf("=============Program End==============

");

	return 0;
}