RosettaCodeData/Task/Pascal-matrix-generation/ALGOL-68/pascal-matrix-generation.alg

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BEGIN
# returns an upper Pascal matrix of size n #
PROC upper pascal matrix = ( INT n )[,]INT:
BEGIN
[ 1 : n, 1 : n ]INT result;
FOR j TO n DO result[ 1, j ] := 1 OD;
FOR i FROM 2 TO n DO
result[ i, 1 ] := 0;
FOR j FROM 2 TO n DO
result[ i, j ] := result[ i - 1, j - 1 ] + result[ i, j - 1 ]
OD
OD;
result
END # upper pascal matrix # ;
# returns a lower Pascal matrix of size n #
PROC lower pascal matrix = ( INT n )[,]INT:
BEGIN
[ 1 : n, 1 : n ]INT result;
FOR i TO n DO result[ i, 1 ] := 1 OD;
FOR j FROM 2 TO n DO
result[ 1, j ] := 0;
FOR i FROM 2 TO n DO
result[ i, j ] := result[ i - 1, j - 1 ] + result[ i - 1, j ]
OD
OD;
result
END # lower pascal matrix # ;
# returns a symmetric Pascal matrix of size n #
PROC symmetric pascal matrix = ( INT n )[,]INT:
BEGIN
[ 1 : n, 1 : n ]INT result;
FOR i TO n DO
result[ i, 1 ] := 1;
result[ 1, i ] := 1
OD;
FOR j FROM 2 TO n DO
FOR i FROM 2 TO n DO
result[ i, j ] := result[ i, j - 1 ] + result[ i - 1, j ]
OD
OD;
result
END # symmetric pascal matrix # ;
# print the matrix m with the specified field width #
PROC print matrix = ( [,]INT m, INT field width )VOID:
BEGIN
FOR i FROM 1 LWB m TO 1 UPB m DO
FOR j FROM 2 LWB m TO 2 UPB m DO
print( ( " ", whole( m[ i, j ], - field width ) ) )
OD;
print( ( newline ) )
OD
END # print matrix # ;
print( ( "upper:", newline ) ); print matrix( upper pascal matrix( 5 ), 2 );
print( ( "lower:", newline ) ); print matrix( lower pascal matrix( 5 ), 2 );
print( ( "symmetric:", newline ) ); print matrix( symmetric pascal matrix( 5 ), 2 )
END