Another update from ingydotnet^djgoku

Task/Conditional-structures/ALGOL-W/conditional-structures.alg

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+begin
+    integer a, b, c;
+
+    a := 1; b := 2; c := 3;
+
+    % algol W has the traditional Algol if-the-else statement                %
+    % there is no "elseif" contraction                                       %
+    if a = b
+    then write( "a = b" )
+    else if a = c
+         then write( "a = c" )
+         else write( "a is ", a );
+
+    % if-then-else can also be used in an expression                         %
+    write( if a < 4 then "lt 4" else "ge 4" );
+
+    % algol W also has a "case" statement, an integer expression is used to  %
+    % select the statement to execute. If the expression evaluates to 1,    %
+    % the first statement is executed, if 2, the second is executed etc.     %
+    % If the expression is less than 1 or greater than the number of         %
+    % statements, a run time error occurs                                    %
+    case a + b of
+    begin write( "a + b is one"   )
+        ; write( "a + b is two"   )
+        ; write( "a + b is three" )
+        ; write( "a + b is four"  )
+    end;
+
+    % there is also an expression form of the case:                          %
+    write( case c - a of ( "one", "two", "three", "four" ) )
+
+end.