Data commit

Task/Population-count/ALGOL-W/population-count.alg

@@ -0,0 +1,69 @@
+begin
+    % returns the population count (number of bits on) of the non-negative integer n %
+    integer procedure populationCount( integer value n ) ;
+            begin
+                integer v, count;
+                v     := n;
+                count := 0;
+                while v > 0 do begin
+                    if odd( v ) then count := count + 1;
+                    v     := v div 2
+                end while_v_gt_0 ;
+                count
+            end populationCount ;
+    % returns the sum of population counts of the elements of the array n            %
+    %         the bounds of n must be 1 :: length                                    %
+    integer procedure arrayPopulationCount( integer array n ( * ); integer value length ) ;
+            begin
+                integer count;
+                count := 0;
+                for i := 1 until length do count := count + populationCount( n( i ) );
+                count
+            end arrayPopulationCount ;
+    begin %task requirements %
+        integer array power( 1 :: 8 );
+        integer n, count, carry;
+        % population counts of the first 30 powers of three %
+        % Algol W integers are 32-bit, so we simulate 64-bit with an array of integers %
+        % the only operation we need is multiplication by 3                            %
+        % we use 8 bits of each number                                                 %
+        % start with 3^0, which is 1 %
+        for i := 1 until 8 do power( i ) := 0;
+        power( 1 ) := 1;
+        write( i_w := 1, s_w := 0, "3^x  population: ", arrayPopulationCount( power, 8 ) );
+        for p := 1 until 29 do begin
+            carry := 0;
+            for b := 1 until 8 do begin
+                integer bValue;
+                bValue     := ( power( b ) * 3 ) + carry;
+                carry      := bValue div 256;
+                power( b ) := bValue rem 256
+            end for_b ;
+            writeon( i_w := 1, s_w := 0, " ", arrayPopulationCount( power, 8 ) )
+        end for_p ;
+
+        % evil numbers (even population count) %
+        write( "evil    numbers:" );
+        n     := 0;
+        count := 0;
+        while count < 30 do begin
+            if not odd( populationCount( n ) ) then begin
+                writeon( i_w := 1, s_w := 0, " ", n );
+                count := count + 1
+            end if_not_odd_populationCount ;
+            n := n + 1
+        end evil_numbers_loop ;
+
+        % odious numbers (odd population count %
+        write( "odious  numbers:" );
+        n     := 0;
+        count := 0;
+        while count < 30 do begin
+            if odd( populationCount( n ) ) then begin
+                writeon( i_w := 1, s_w := 0, " ", n );
+                count := count + 1
+            end if_odd_populationCount ;
+            n := n + 1
+        end odious_numbers_loop
+   end
+end.