#include <stddef.h>
#include <stdbool.h>

bool isdigit(char c)
{
	return c >= 48 && c <= 57;
}

size_t strlen(const char *s)
{
	size_t c = 0;

	while (s[c])
		c++;

	return c;
}

size_t strnlen(const char *s, size_t maxlen)
{
	size_t c = 0;

	while (c <= maxlen && s[c])
		c++;

	return c;
}

char *strcpy(char *restrict dst, const char *restrict src)
{
	size_t pos = 0;
	size_t len = strlen(src) + 1;

	for(pos = 0; pos <= len; pos++)
		dst[pos] = src[pos];

	return dst;
}

void *memset(void *s, int c, size_t n) {

	char *cur = (char*) s;
	int i;

	for (i = 0; i < n; i++)
		cur[i] = (unsigned char)c;

	return s;
}