Min and max functions in c

min_max.h

#include "stdio.h"
#include "stdlib.h"
#include "stdarg.h"

/**
 * The maxOf function takes in any number of signed integers preceded by the amount of arguments (not including the first one) that
 * it receives and returns the biggest number amongst all of it's arguments
 * example usage:
 * maxOf(5, 56, 34, 345, 1235, 90686); should return 90686*/
int maxOf(int num, ...)
{
	va_list args;
	int max;
	/*register keyword may not be needed*/
	register int i;
	va_start(args, num);
	for (i = 0; i < num; i++)
	{
		int a = va_arg(args, int);
		if (a > max) max = a;
	}
	va_end(args);
	return max;
}

/**
 * The minOf function takes in any number of signed integers preceded by the amount of arguments (not including the first one) that
 * it receives and returns the smallest number amongst all of it's arguments
 * example usage:
 * minOf(5, 56, 34, 345, 1235, 90686); should return 5*/
int minOf(int num, ...)
{
	va_list args;
	int min;
	/*register keyword may not be needed*/
	register int i;
	va_start(args, num);
	for (i = 0; i < num; i++)
	{
		int a = va_arg(args, int);
		if (a < min) min = a;
	}
	va_end(args);
	return min;
}