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September 2017 Update

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Ingy döt Net 2017-09-23 10:01:46 +02:00
parent bba7bfd280
commit ba8067c3b7
14570 changed files with 153136 additions and 63871 deletions
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51
Task/Stack/ALGOL-W/stack.alg Normal file
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begin
% define a Stack type that will hold StringStackElements %
% and the StringStackElement type %
% we would need separate types for other element types %
record StringStack ( reference(StringStackElement) top );
record StringStackElement ( string(8) element
; reference(StringStackElement) next
);
% adds e to the end of the StringStack s %
procedure pushString ( reference(StringStack) value s
; string(8) value e
) ;
begin
reference(StringStackElement) newElement;
top(s) := StringStackElement( e, top(s) )
end pushString ;
% removes and returns the top element from the StringStack s %
% asserts the Stack is not empty, which will stop the %
% program if it is %
string(8) procedure popString ( reference(StringStack) value s ) ;
begin
string(8) v;
assert( not isEmptyStringStack( s ) );
v := element(top(s));
top(s):= next(top(s));
v
end popStringStack ;
% returns the top element of the StringStack s %
% asserts the Stack is not empty, which will stop the %
% program if it is %
string(8) procedure peekStringStack ( reference(StringStack) value s ) ;
begin
assert( not isEmptyStringStack( s ) );
element(top(s))
end popStringStack ;
% returns true if the StringStack s is empty, false otherwise %
logical procedure isEmptyStringStack ( reference(StringStack) value s ) ; top(s) = null;
begin % test the StringStack operations %
reference(StringStack) s;
s := StringStack( null );
pushString( s, "up" );
pushString( s, "down" );
pushString( s, "strange" );
pushString( s, "charm" );
while not isEmptyStringStack( s ) do write( popString( s )
, if isEmptyStringStack( s ) then "(empty)"
else peekStringStack( s )
)
end
end.