calcu.exe 表达式计算器，Pascal语言，原创

program expression_calculator;
uses windows,dos;
label calc,head;
var
a,r:string;
f,n:array [1..100] of string;
i,j,k,l,lqu,rqu:integer;
t,u:real;
fl1,fl2:text;
p:boolean;
begin
a:=paramstr(1);
a:='('+a+')';
p:=false;
if paramstr(2)='/p' then p:=true;
head:write('');
assign(fl1,'calc.mfc');
assign(fl2,'calc.mfc');
for i:=1 to 100 do begin
 f[i]:='';
 n[i]:='';
end;
lqu:=0;
rqu:=length(a);
for i:=1 to length(a) do begin
 if a[i]='(' then lqu:=i;
 if a[i]=')' then begin rqu:=i;goto calc end;
end;
calc:j:=1;
for i:=lqu to rqu do
 case a[i] of
  '1','2','3','4','5','6','7','8','9','0','.':n[j]:=n[j]+a[i];
  '+','-','*','/':begin j:=j+2;f[j-1]:=a[i] end;
 end;
for i:=2 to j do
 for k:=i-1 downto 1 do
  if n[k]<>'' then
   for l:=i+1 to j do
    if n[l]<>'' then begin
     val(n[k],t);
     val(n[l],u);
     case f[i] of
      '*':begin rewrite(fl1);t:=t*u;write(fl1,t:0:5);close(fl1);reset(fl2);read(fl2,n[i]);close(fl2);n[k]:='';n[l]:='';f[i]:='' end;
      '/':begin rewrite(fl1);t:=t/u;write(fl1,t:0:5);close(fl1);reset(fl2);read(fl2,n[i]);close(fl2);n[k]:='';n[l]:='';f[i]:='' end;
     end;
    end;
for i:=2 to j do
 for k:=i-1 downto 1 do
  if n[k]<>'' then
   for l:=i+1 to j do
    if n[l]<>'' then begin
     val(n[k],t);
     val(n[l],u);
     case f[i] of
      '+':begin rewrite(fl1);t:=t+u;write(fl1,t:0:5);close(fl1);reset(fl2);read(fl2,n[i]);close(fl2);n[k]:='';n[l]:='';f[i]:='' end;
      '-':begin rewrite(fl1);t:=t-u;write(fl1,t:0:5);close(fl1);reset(fl2);read(fl2,n[i]);close(fl2);n[k]:='';n[l]:='';f[i]:='' end;
     end;
    end;
r:='';
for i:=1 to j do
 if n[i]<>'' then r:=n[i];
delete(a,lqu,rqu+1-lqu);
insert(r,a,lqu);
if p then writeln(a);
if not((pos('+',a)=0) and (pos('-',a)=0) and (pos('*',a)=0) and (pos('/',a)=0)) then goto head;
if not(p) then writeln(a);
exec('C:\Windows\system32\cmd.exe','/c del /f /q calc.mfc >nul 2>nul');
end.
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