MATLAB: How to print out a product of 2 requested numbers

functionsprint function

I need to write a function that requests the user to input 2 numbers one by one and then prints them and their prodct according to:

(I'm using the example numbers it gives me)

>> print_product Give me a number: 4 Give me another number: 7 The product of 4 and 7 is 28.

function [] = print_product ()
clc
x = input('Give me a number:  ', 's');
y = input('Give me another number:  ', 's');
z = x*y;
fprintf ('The product of x and y is z  ')

Best Answer

function print_product()
x = str2double(input('Give me a number:  ', 's'));
y = str2double(input('Give me another number:  ', 's'));
z = x*y
fprintf('The product of %d and %d is %d',x,y,z)
end

Related Solutions

MATLAB: Find the alphabetic word product

See the code below for some more guided hints in an almost finished form. You don't need to call the input function btw. You can call the function by using e.g.

word_product('hello')

If you see a function you don't know, read its documentation. For most common tasks there exists a Matlab function. As an example: the sum function will calculate the sum of an array. Generally a combination of Google, the documentation, and guesses will get you there.

function p=word_product(s)
%convert a word to a ceasar cypher product
%(i.e. convert letters to numbers (a=A=1, b=B=2, etc), and calculate the
%product of these numbers)
%convert all letters to lowercase so we don't need to worry about uppercase
s=SomeFunction(s);
%Now convert the letters to numbers
%This can be done with a tedious lookup for all 26 cases, but this is
%Matlab, there is probably an easier way; and luckily there is.
s=double(s);
%This is not yet correct (nor technically even needed for the next step),
%so you will have to do an extra edit.
%Check out what double() does to char arrays (run in command window):
%double('a')
%double('ab')
%Now we can calculate the product:
p=SomeOtherFunction(s);
end

MATLAB: How to find number of significant figures in a decimal number

This is not necessarily trivial to do reliably. In the first place, 31.456 is not representable in IEEE double exactly, so those trailing digits aren't really exactly all 0's anyway. E.g.,

>> num2strexact(31.456)
ans =
3.1455999999999999516830939683131873607635498046875e1

So, depending on how one prints the number out and how one sorts though all the trailing digits you can get a variety of answers. One approach might be to start with the exact string, as above, and then progressively round the last digit and re-read the result to see if you end up with the same IEEE double number. When it doesn't match, then you know you hit the smallest "significant" digit (assuming I understand what you mean by the term).

EDIT

OK, so here is a quick first cut at a function based on the idea above. Hasn't been extensively tested so caveat emptor. Seems to work for the few test cases I have thrown at it. Is not vectorized, although that could easily be done. (I hesitate to post this because I have this nagging suspicion that this could be done in a simpler way, but what the heck ...)

% SIGDIGITS returns significant digits in a numeric non-uint64 number.
% Returns "significant" digits in a number, in the sense that if you
% printed any fewer digits the reverse conversion would not equal the
% original number. I.e., the value returned from this function is the
% minimum number of digits you must print in order to recover the original
% number with a reverse conversion.
% Programmer: James Tursa
function n = sigdigits(x)
if( ~isnumeric(x) || ~isfinite(x) || isa(x,'uint64') )
    error('Need any finite numeric type except uint64');
end
if( x == 0 )
    n = 0;
    return;
end
x = abs(x);
y = num2str(x,'%25.20e'); % Print out enough digits for any double
z = [' ' y]; % Pad beginning to allow rounding spillover
n = find(z=='e') - 1; % Find the exponent start
e = n;
while( str2double(y) == str2double(z) ) % While our number is still equal to our rounded number
    zlast = z;
    c = z(e); % Least significant printed digit
    if( c == '.' )
        e = e - 1;
        c = z(e);
    end
    z(e) = '0'; % 0 the least significant printed digit
    e = e - 1;
    if( c >= '5' ) % Round up if necessary
        c = z(e);
        if( c == '.' )
            e = e - 1;
            c = z(e);
        end
        while( true ) % The actual rounding loop
            if( c == ' ' )
                z(e) = '1';
                break;
            elseif( c < '9' )
                z(e) = z(e) + 1;
                break;
            else
                z(e) = '0';
                e = e - 1;
                c = z(e);
                if( c == '.' )
                    e = e - 1;
                    c = z(e);
                end
            end
        end
    end
end
n = n - 1;
z = zlast(1:n); % Get rid of exponent
while( z(n) == '0' ) % Don't count trailing 0's
    n = n - 1;
end
n = n - 2; % Don't count initial blank and the decimal point.
end

Best Answer

Related Solutions

MATLAB: Find the alphabetic word product

MATLAB: How to find number of significant figures in a decimal number

Related Question