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program project3;
uses StackPackageForSolveExpression,StackPackageForConvertExpression;
const
D1=['0'..'9'];
D2 = ['-','+','*','/'];
function Priority (Var aCh :Char):integer;
begin
case aCh of
'*','/': Priority:=3;
'+','-': Priority:=2;
'(': Priority:=1;
end;
end;
function StringToReal(StringElement: string): real;
var
RealResult,c: integer;
begin
val(StringElement,RealResult,c);
if c<>0 then RealResult:=0;
StringToReal:=RealResult;
end;
function ResultOfExpression(var S1: string):real;
var
j:integer;
BinaryResult,a,b,IntResult :real;
begin
InitStack1;
for j:=1 to Length(S1) do
begin
if S1[j] in D1 then
begin
IntResult:=StrToInt(S1[j]);
IntStackPush(IntStack,IntResult);
end
else
if S1[j] in D2 then
begin
a:= IntStackPop(IntStack);
b:= IntStackPop(IntStack);
case S1[j] of
'+':BinaryResult:=a+b;
'-':BinaryResult:=b-a;
'*':BinaryResult:=a*b;
'/':BinaryResult:=b/a;
end;
IntStackPush(IntStack,BinaryResult);
end;
end;
with IntStack do
begin
ResultOfExpression:=IntData[IntTop];
end;
end;
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