// FOR LOOP IN Java / C / C++
/////////////////////////////

int f( int x, int y ) {
    int c;
    int d;
    int result;
    
    result = 0;
    for (c = 1; c <= x; c++) {
        for (d = x; d <= y; d++) {
            if (c % 2 == 0 && d % 2 == 0) {
                result += c + d;
            }
        }
    }
    
    return result;
}


-- FOR LOOP IN Haskell
----------------------

f x y = foldr1 (+) [c+d | c <- [1..x], d <- [x..y], mod c 2 == 0, mod d c == 0]


% FOR LOOP IN Prolog
%%%%%%%%%%%%%%%%%%%%

listsum( [], 0 ) :- !.
listsum( [A|As], S ) :- listsum( As, S1 ),
                        S is A + S1.
                        
loopbody( X, Y, Sum ) :- for( C, 1, X ),
                         for( D, X, Y ),
                         0 is C mod 2,
                         0 is D mod C,
                         Sum is C + D.
                         
f( X, Y, Result ) :- bagof( S, loopbody( X, Y, S ), Lst ),
                     listsum( Lst, Result ).


////////////////////////////////////////////////////////////////////////////////
--------------------------------------------------------------------------------
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


// IF-THEN IN Java / C / C++ (version 1)
////////////////////////////////////////

int ifthen( int x ) {
    int y;
    
    if (p(x)) {
        y = 1;
    } else {
        y = 2;
    }
    
    return y;
}

// IF-THEN IN Java / C / C++ (version 2)
////////////////////////////////////////

int ifthen( int x ) {
    int y;
    
    y = (p(x) ? 1 : 2);
    
    return y;
}


-- IF-THEN IN Haskell
---------------------

ifthen x = y where
    y = if (p x) then 1
                 else 2


%% IF-THEN IN Prolog (version 1)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

ifthen( X, Y ) :- ((p( X ), Y = 1, !);
                   Y = 2).
                   
%% IF-THEN IN Prolog (version 2)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

ifthen( X, Y ) :- (p( X ) -> Y = 1 ; Y = 2).


////////////////////////////////////////////////////////////////////////////////
--------------------------------------------------------------------------------
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


// SWITCH / CASE IN Java / C / C++
//////////////////////////////////

int f( int x ) {
    int y;
    
    switch (x) {
        case 1:
            y = 2;
            break;
        case 2:
            y = 4;
            break;
        default:
            y = 0;
    }

    return y;
}


-- SWITCH / CASE IN Haskell (version 1)
---------------------------------------

f 1 = 2
f 2 = 4
f _ = 0

(or)

f x | x == 1    = 2
    | x == 2    = 4
    | otherwise = 0

-- SWITCH / CASE IN Haskell (version 2)
---------------------------------------

f x = case x of
    1 -> 2
    2 -> 4
    _ -> 0


%% SWITCH / CASE IN Prolog (version 1)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

f( 1, 2 ) :- !.
f( 2, 4 ) :- !.
f( _, 0 ).

%% SWITCH / CASE IN Prolog (version 2)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

f( X, Y ) :- % ... ,
             ((X is 1, Y is 2, !);
              (X is 2, Y is 4, !);
               Y is 0).