Shift list elements to left by 3: Difference between revisions
Added Algol W
(→{{header|ALGOL 68}}: Tweak) |
(Added Algol W) |
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print( ( newline ) )
END</lang>
{{out}}
<pre>
[1,2,3,4,5,6,7,8,9] -> [4,5,6,7,8,9,1,2,3]
</pre>
=={{header|ALGOL W}}==
{{Trans|ALGOL 68}}
<lang pascal>begin
% increments a and returns the new value %
integer procedure inc ( integer value result a ) ; begin a := a + 1; a end;
% shifts in place the elements of a left by n, a must have bounds lb::ub %
procedure rotateLeft ( integer array a ( * ); integer value lb, ub, n ) ;
if n < ( ub - lb ) and n > 0 then begin
% the amount to shift is less than the length of the array %
integer array shifted ( 1 :: n );
integer aPos;
aPos := lb - 1;
for i := 1 until n do shifted( i ) := a( inc( aPos ) );
for i := lb until ub - n do a( i ) := a( i + n );
aPos := ub - n;
for i := 1 until n do a( inc( aPos ) ) := shifted( i );
end rotateLeft ;
% prints the elements of v from lb to ub %
procedure printArray ( integer array v ( * ); integer value lb, ub ) ;
begin
writeon( s_w := 0, "[" );
if lb <= ub then begin
writeon( i_w := 1, s_w := 0, v( lb ) );
for i := lb + 1 until ub do writeon( i_w := 1, s_w := 0, "," , v( i ) )
end;
writeon( s_w := 0, "]" )
end printArray ;
begin
integer array v ( 1 :: 9 );
for i := 1 until 9 do v( i ) := i;
printArray( v, 1, 9 );
writeon( " -> " );
rotateLeft( v, 1, 9, 3 );
printArray( v, 1, 9 );
write()
end
end.</lang>
{{out}}
<pre>
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