Implementing a strcpy so that you can copy multiple strings.

strcopy.c

#include <stdio.h>
#include <stdarg.h>

#define STRCOPY(destination, num, ...) strcopy(destination, num, __VA_ARGS__, NULL)
char* strcopy(char*, size_t, ...);

int main(void)
{
	char dest[10 + 1];
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World!"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World", "alvarez!"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World!!"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", ""));
	getchar();
    return 0;
}

char* strcopy(char* destination, size_t num, ...)
{
	va_list list;
	va_start(list, num);
	num -= 1;
	size_t i = 0;
	char* source = va_arg(list, char*);
	while(source != NULL && i < num)
	{
		for(size_t j = 0; source[j] != '\0' && i < num; ++j, ++i)
			destination[i] = source[j];
		source = va_arg(list, char*);
	}
	destination[i] = '\0';
	va_end(list);
	return destination;
}

strcopyV2.c

#include <stdio.h>
#include <stdarg.h>

#define STRCOPY(destination, num, ...) strcopy(destination, num, __VA_ARGS__, NULL)
char* strcopy(char*, size_t, ...);

int main(void)
{
	char dest[10 + 1];
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World!"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World", "alvarez!"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", "World!!"));
	printf("%s\n", STRCOPY(dest, sizeof dest, "Hello", ""));
	getchar();
    return 0;
}

char* strcopy(char* destination, size_t num, ...)
{
	va_list list;
	va_start(list, num);
	num -= 1;
	char* dest = destination;
	char* source = va_arg(list, char*);
	while(source != NULL && num != 0)
	{
		for(; *source != '\0' && num != 0; ++source, ++dest, --num)
			*dest = *source;
		source = va_arg(list, char*);
	}
	*dest = '\0';
	va_end(list);
	return destination;
}