CareerCup

I think subString() internally calls String(char[],offset,count)
Thats why memory lickage would be occured this is the drawback of subString()
please tell me if i wrong

int substr_reentrant(char* str, char* substr_out, int outlen, int pos =0, int count=-1)
{
	if (!str || *str == '\0')
        {
		return 0;
        }
	if (pos < 0 || pos >= strlen(str))
		return 0;
	if (count != -1)
	{
		if (pos+count > strlen(str))
		{
			return 0;
		}
	}
	if (count == -1)
	{
		strcpy(substr_out, str+pos);
	}
	else
	{
		strncpy(substr_out, str+pos, count);
		substr_out[count]='\0';
	}
	return 1;
}