Data commit

Task/Pascal-matrix-generation/ALGOL-W/pascal-matrix-generation.alg

@@ -0,0 +1,66 @@
+begin
+    % initialises m to an upper Pascal matrix of size n %
+    % the bounds of m must be at least 1 :: n, 1 :: n   %
+    procedure upperPascalMatrix ( integer array m( *, * )
+                                ; integer value n
+                                ) ;
+    begin
+        for j := 1 until n do m( 1, j ) := 1;
+        for i := 2 until n do begin
+            m( i, 1 ) := 0;
+            for j := 2 until n do m( i, j ) := m( i - 1, j - 1 ) + m( i, j - 1 )
+        end for_i
+    end upperPascalMatrix ;
+
+    % initialises m to a lower Pascal matrix of size n  %
+    % the bounds of m must be at least 1 :: n, 1 :: n   %
+    procedure lowerPascalMatrix ( integer array m( *, * )
+                               ; integer value n
+                               ) ;
+    begin
+        for i := 1 until n do m( i, 1 ) := 1;
+        for j := 2 until n do begin
+            m( 1, j ) := 0;
+            for i := 2 until n do m( i, j ) := m( i - 1, j - 1 ) + m( i - 1, j )
+        end for_j
+    end lowerPascalMatrix ;
+
+    % initialises m to a symmetric Pascal matrix of size n %
+    % the bounds of m must be at least 1 :: n, 1 :: n   %
+    procedure symmetricPascalMatrix ( integer array m( *, * )
+                                    ; integer value n
+                                    ) ;
+    begin
+        for i := 1 until n do begin
+            m( i, 1 ) := 1;
+            m( 1, i ) := 1
+        end for_i;
+        for j := 2 until n do for i := 2 until n do m( i, j ) := m( i, j - 1 ) + m( i - 1, j )
+    end symmetricPascalMatrix ;
+
+    begin % test the pascal matrix procedures %
+
+        % print the matrix m with the specified field width %
+        % the bounds of m must be at least 1 :: n, 1 :: n   %
+        procedure printMatrix ( integer array m( *, * )
+                              ; integer value n
+                              ; integer value fieldWidth
+                              ) ;
+        begin
+            for i := 1 until n do begin
+                write(                         i_w := fieldWidth, s_w := 0, " ", m( i, 1 ) );
+                for j := 2 until n do writeon( i_w := fieldWidth, s_w := 0, " ", m( i, j ) )
+            end for_i
+        end printMatrix ;
+
+        integer array m( 1 :: 10, 1 :: 10 );
+        integer n, w;
+
+        n := 5; w := 2;
+        upperPascalMatrix(     m, n ); write( "upper:"     ); printMatrix( m, n, w );
+        lowerPascalMatrix(     m, n ); write( "lower:"     ); printMatrix( m, n, w );
+        symmetricPascalMatrix( m, n ); write( "symmetric:" ); printMatrix( m, n, w )
+
+    end
+
+end.