Type Casting?

This is a discussion on Type Casting? within the C++ Programming forums, part of the General Programming Boards category; Ok what in looking to do is for the user to imput any givin number of chars, then in turn ...

  1. #1
    Registered User
    Join Date
    Aug 2001
    Posts
    57

    Type Casting?

    Ok what in looking to do is for the user to imput any givin number of chars, then in turn convert those chars in to ints.
    Actually not just any ints its sequenced into multiples of six like eg. (A=6, B=12, C=18,... Z=156)

    im thinking type casting might be the way to go but there are other factors

    I also want to, once the letters are recieved and converted, the sum of all the imputed/converted values must be calculated.

    Now..im thinkin like going

    char FirstLetterEntered, SecondLetterEntered,Third ......ect
    //get the imput
    Then mabey...

    if ( FirstLetterEntered == "A"||"a")
    FirstLetterEntered = 6; //would have to cast here??

    But i would have to do it for every one and then again for the second and so on , I know there is a better way i just need some structuring advice
    =@-OmegatronO-@=

  2. #2
    Registered User The Dog's Avatar
    Join Date
    May 2002
    Location
    Cape Town
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    788
    Here's one way to do it.

    Declare FirstLetterEntered as an int eg.

    int FirstLetterEntered;

    then assign the user's input character to FirstLetterEntered, eg.

    FirstLetterEntered = getch(); //getch() is not ANSI compliant
    Code:
    if( (FirstLetterEntered >=97 && FirstLetterEntered <=122) || (FirstLetterEntered >=65 && FirstLetterEntered <= 90) )
    {
         if(FirstLetterEntered >=97 && FirstLetterEntered <=122)
         {
              FirstLetterEntered = (FirstLetterEntered - 96) * 6;
              break;
         }
         if(FirstLetterEntered >=65 && FirstLetterEntered <=90)
              FirstLetterEntered = (FirstLetterEntered - 65) * 6;
    }
    just plonk that in a loop, and there you go

  3. #3
    Registered User The Dog's Avatar
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    one flaw:
    Code:
    if( (FirstLetterEntered >=97 && FirstLetterEntered <=122) || (FirstLetterEntered >=65 && FirstLetterEntered <= 90) )
    {
         if(FirstLetterEntered >=97 && FirstLetterEntered <=122)
         {
              FirstLetterEntered = (FirstLetterEntered - 96) * 6;
              break;
         }
         if(FirstLetterEntered >=65 && FirstLetterEntered <=90)
              FirstLetterEntered = (FirstLetterEntered - 64) * 6;
    }

  4. #4
    Razzer
    Guest

    Talking

    Here's my solution. It could easily be pulled down a bit, but its fun to work with .

    Code:
    #include <valarray>
    #include <iostream>
    #include <vector>
    #include <numeric>
    #include <cctype>
    
    //Conversion
    inline unsigned char convert( unsigned char ch ) { return tolower(ch) - 'a' + 1; }
    
    int main( void )
    {
    	std::vector< unsigned char > vec; //Need unsigned chars here so we don't overflow
    	unsigned char ch;
    
    	/* Debugging, make sure 'a' == 1
    	for( char ctest = 'a'; ctest <= 'z'; ++ctest )
    		std::cout << static_cast<int>(convert( ctest )) << " ";
    
    	std::cout << std::endl;*/
    
    	while( std::cin >> ch ) //Read until a non-number character pops in
    	{
    		if( !isalpha( ch ) ) break;
    		vec.push_back( convert(ch));
    	}
    
    	std::valarray<unsigned char> array(vec.begin(),vec.size()); //Create the powerful std::valarray for quick computation
    
    	array *= static_cast<unsigned char>(6); //Need to cast, otherwise, it thinks 6 is an int
    
    	int number = std::accumulate( &array[0], &array[array.size()], 0 ); //Add everthing together
    
    	std::cout << number << std::endl; //Output the sum
    
    	return 0;
    }

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