Array Practice
---------------



Problem 1: Write a function that takes 2 vectors and returns the dot product of the two vectors. The two vectors must be the same size

double DotProduct(const double vector1[], const double vector2[], int length)
{
	double product = 0;

	for(int i = 0; i < length; i++)
	{
		product += vector1[i] * vector2[i];
	}

	return product;
}

Problem 2: Make a function called GetCharacter that will take in a cstring prompt, an error cstring, and return a character from stdin from the user. If the user types something incorrectly or the input doesn't match the valid inputs, the function should recover from the failure gracefully and output the error cstring and prompt the user to try again.

char GetCharacter(const char* prompt, const char* error)
{
    char input;
    bool inputFailure;
    
    do {
        
        inputFailure = false;
        std::cout << prompt;

        std::cin >> input;
        
        if (std::cin.fail())
        {
            std::cin.ignore(256, '\n');
            std::cin.clear();
            std::cout<<error<<std::endl;
            inputFailure = true;
        }
        else
        {
            std::cin.ignore(256, '\n');
            if (std::isalpha(input))
	    {
		input = std::tolower(input);
	    }
	    else
	    {
		 std::cout<<error<<std::endl;
                inputFailure = true;
	    }
        }
        
    } while (inputFailure);
    
    return input;
}

Problem 3: Create a new function that called GetCharacter that will also take in valid inputs that the user can type in, and how many there are. The function should only allow those inputs by the user, and give an error if the user doesn't input it correctly.

char GetCharacter(const char* prompt, const char* error, const char validInput[], int validInputLength, CharacterCaseType charCase)
{
    char input;
    bool inputFailure = false;
    
    do {
        
        std::cout << prompt;
		std::cin >> input;
        
        if (std::cin.fail())
        {
            std::cin.ignore(256, '\n');
            std::cin.clear();
            std::cout<<error<<std::endl;
            inputFailure = true;
        }
        else
        {
            std::cin.ignore(256, '\n');
            
            input = std::tolower(input);
                
            for (int i = 0; i < validInputLength; ++i)
            {
                if (input == validInput[i])
                {
                    return input;
                }
            }
            
            std::cout<<error<<std::endl;
            inputFailure = true;
        }
        
    } while (inputFailure);
    
    return ' ';
}