Var a, b, c, x1, x2: real;

Procedure Nhapabc(var aa,bb,cc: real);
Begin
Write('a='); Readln(aa);
Write('b='); Readln(bb);
Write('c='); Readln(cc);
End;

Procedure GPTB2;
Var Delta: real;
Begin
Delta:=sqr(b)-4*a*c;
If Delta<0 then Writeln('Phuong trinh vo nghiem.')
Else
If Delta=0 then
Begin
Write('Phuong trinh co nghiem kep : ');
Write('x1,2=',-b/(2*a):8:2);
End
Else
Begin
x1:=(-b+sqrt(Delta))/(2*a);
x2:=(-b-sqrt(Delta))/(2*a);
Writeln('Phuong trinh co 2 nghiem phan biet la :');
Writeln('X1=',x1:8:2,', X2=',x2:8:2);
End;
End;

BEGIN
Writeln(' Giai Phuong Trinh Bac Hai Voi Cac He So :');
Nhapabc(a,b,c);
If a<>0 then GPTB2
Else Writeln(' Khong phai phuong trinh bac hai ');
Readln ;
END .

                      {In Mang}


var A:array[1..100] of integer;
tong,j,min,max,maxd,csmaxd,i,csmin,csmax,tg,n,tongle,tongchan,demam,demduong,demchan,demle:integer;
tb:real;
begin
writeln('nhap so phan tu: ');readln(n);
for i:=1 to n do
begin
writeln('gia tri phan tu thu ',i,':= ');
readln(a[i]);
end;
readln;
for i:=1 to n do
write(a[i]:4);
readln;

                      {Day Tang Dan}
{
for i:=1 to (n-1) do
for j:=i+1 to n do
if a[i]>a[j] then
begin
tg:=a[i];
a[i]:=a[j];
a[j]:=tg;
end;
for i:=1 to n do
write(a[i]:4);
readln;    }

                      {Day Giam Dan}
{
for i:=1 to (n-1) do
for j:=i+1 to n do
if a[i]<a[j] then
begin
tg:=a[i];
a[i]:=a[j];
a[j]:=tg;
end;
for i:=1 to n do
write(a[i]:4);
readln;  }

                    {Gia Tri Lon Nhat-Nho Nhat}

max:=a[1];
csmax:=1;
for i:=1 to n do
if max<a[i] then
begin
max:=a[i];
csmax:=i;
end;
writeln('phan tu lon nhat la: ',max,',  chi so la: ',csmax);
min:=a[1];
csmin:=1;
for i:=1 to n do
if min>a[i] then
begin
min:=a[i];
csmin:=i;
end;
writeln('phan tu be nhat la: ',min,',  chi so la: ',csmin);
readln;


                        {Tinh Tong-Trung Binh Cong}

tong:=0;
for i:=1 to n do
begin
tong:=tong+a[i];
tb:=tong/n;
end;
writeln('tong cua cac phan tu la: ',tong:6);
writeln('trung binh cong cua cac phan tu la: ',tb:6:2);
readln;

                        {Tong cac so chan-le}

tongchan:=0;
tongle:=0;
for i:=1 to n do
begin
if a[i]>0 then
tongchan:=tongchan+a[i];
if a[i]<0 then
tongle:=tongle+a[i];
end;
writeln('tong cac so chan:= ',tongchan);
writeln('tong cac so le:= ',tongle);
readln;

                          {Tong Cac so am-duong}

demduong:=0;
demam:=0;
for i:=1 to n do
begin
if a[i]>0 then demduong:=demduong+1;
if a[i]<0 then demam:=demam+1;
end;
writeln('co tat ca ',demduong,' so duong');
writeln('co tat ca ',demam,' so am');
readln;

                      {Co bao nhieu so chan-le}

demchan:=0;
demle:=0;
for i:=1 to n do
begin
if (a[i] mod 2=0) and (a[i]<>0) then demchan:=demchan+1;
if (a[i] mod 2=1) or (a[i] mod 2=-1) then demle:=demle+1;
end;
writeln('co tat ca ',demchan,' so chan');
writeln('co tat ca ',demle,' so le');
readln;

                  {Phan tu duong dau tien-cuoi cung}

i:=1;
while (i<=n) and (a[i]<0) do i:=i+1;
if i>n then
writeln('khong co phan tu duong dau tien') else
writeln('phan tu duong dau tien la',a[i]:4,',  chi so la: ',i:2);
i:=n;
while (i>=1) and (a[i]<0) do i:=i-1;
if i<1 then
writeln('khong co phan tu duong cuoi cung') else
writeln('phan tu duong cuoi cung la: ',a[i]:4,',  chi so la: ',i:2);
readln;

                        {Phan tu am dau tien-cuoi cung}

i:=1;
while (i<=n) and (a[i]>=0) do i:=i+1;
if i>n then
writeln('khong co phan tu am dau tien') else
writeln('phan tu am dau tien la',a[i]:4,',  chi so la: ',i:2);
i:=n;
while (i>=1) and (a[i]>=0) do i:=i-1;
if i<1 then
writeln('khong co phan tu am cuoi cung') else
writeln('phan tu am cuoi cung la: ',a[i]:4,',  chi so la: ',i:2);
readln;

                  {Phan tu chan dau tien-cuoi cung}

i:=1;
while (i<=n) and (a[i] mod 2=1) do i:=i+1;
if (i>n) or (i=0) then
writeln('khong co phan tu chan dau tien') else
writeln('phan tu chan dau tien la: ',a[i]:4,',  chi so la: ',i:2);
i:=n;
while (i>=1) and (a[i] mod 2=1) do i:=i-1;
if i<1 then
writeln('khong co phan tu chan cuoi cung') else
writeln('phan tu chan cuoi cung la: ',a[i]:4,',  chi so la: ',i:2);
readln;

                    {Phan tu le dau tien-cuoi cung}

i:=1;
while (i<=n) and (a[i] mod 2=0) do i:=i+1;
if i>n then
writeln('khong co phan tu le dau tien') else
writeln('phan tu le dau tien la: ',a[i]:4,',  chi so la: ',i:2);
i:=n;
while (i>=1) and (a[i] mod 2=0) do i:=i-1;
if i<1 then
writeln('khong co phan tu le cuoi cung') else
writeln('phan tu le cuoi cung la: ',a[i]:4,',  chi so la: ',i:2);
readln;


                    {Tim so duong be nhat}


i:=1;
while(i<=n) and (a[i]<=0) do i:=i+1;
if i>n then write('khong co phan tu duong be nhat') else
begin
if a[i]>0  then
maxd:=a[i];
csmaxd:=i;
for i:=csmaxd to n do
if (a[i]<=maxd) and (a[i]>0) then
begin
maxd:=a[i];
csmaxd:=i;
end;
write('co so duong be nhat: ',maxd,', chi so: ',csmaxd);
end;
readln;
writeln;



writeln('nhan enter de tro lai');
readln;
end.

                      {Nhap xau-in xau dao}


var
st:string;
max,i,n,k,j,demkitu,demtu:integer;
ch:char;
a:string;
dem:array['A'..'Z'] of integer;
begin
writeln('xau can nhap la:');
readln(st) ;
writeln('xau dao cua xau tren la:');
for i:=length(st) downto 1 do
write(st[i]);
readln;
writeln;


        {so lan xuat hien cua ki tu-ki tu xuat hien nhieu lan nhat}

for i:=1 to length(st) do
st[i]:=upcase(st[i]);
for ch:='A' to 'Z' do dem[ch]:=0;
for i:=1 to length(st) do
if (st[i]>='A') and (st[i]<='Z') then dem[st[i]]:=dem[st[i]]+1;
for ch:='A' to 'Z' do
if dem[ch]>=1 then
writeln('ki tu ',ch,' xuat hien ',dem[ch],' lan');
max:=0;
for ch:='A' to 'Z' do
if dem[ch]>=max then max:=dem[ch];
for ch:='A' to 'Z' do
if dem[ch]=max then
writeln('ki tu ',ch,' xuat hien nhieu lan nhat, voi ',max,' xuat hien');
readln;
writeln;


                {chuyen ki tu thanh hoa-thuong}

writeln('xau duoc chuyen thanh ki tu hoa:');
for i:=1 to length(st) do
st[i]:=upcase(st[i]);
for i:=1 to length(st) do
write(st[i]);
readln;
writeln('xau duoc chuyen thanh ki tu thuong:');
for i:=1 to length(st) do
if (st[i]>='A') and (st[i]<='Z') then
st[i]:=chr(ord(st[i])+32);
for i:=1 to length(st) do
write(st[i]);
readln;
writeln;




                  {kiem tra xau Palidrom}

a:='';
for i:= length(st) downto 1 do
a:=a+st[i];
if a=st then
write('xau vua nhap la xau Palidrom') else
write('xau vua nhap khong la xau Palidrom');
readln;
writeln;


                      {chuan hoa xau}

while st[i]=' ' do delete(st,1,1);
while st[length(st)]=' '  do delete(st,length(st),1);
k:=pos('  ',st);
while k>0 do
begin
delete(st,k,1);
k:=pos('  ',st);
end;
writeln('xau da duoc chuan hoa:');
for i:=1 to length(st) do
write(st[i]);
readln;
writeln;

            {so tu co trong xau}

demtu:=1;
for i:=1 to length(st) do
for j:=i+1 to length(st) do
if st[i]=' ' then
begin
demtu:=demtu+1;
i:=j;
end;
writeln('xau co ',demtu,' tu');
readln;
writeln;

              {xau viet hoa ki tu dau tien cua moi tu}

writeln('xau viet dung chinh ta la: ');
st[1]:=upcase(st[1]);
for i:=1 to length(st) do
if st[i]=' ' then
begin
st[i+1]:=upcase(st[i+1]);
end;
for i:=1 to length(st) do
write(st[i]);
readln;
writeln;




write('nhan enter de tro lai');
readln;
end.

var tep1,tep2:text;
 i,n:integer;
 th,lt,tb:real;
begin
 assign(tep1,'E:\a.txt');
 rewrite(tep1);
 write('nhap so luong hoc sinh: ');readln(n);
for i:=1 to n do
 begin
  writeln('diem hoc sinh thu ',i,':');
  write('diemm li thuyet: ');readln(lt);
  write('diem thuc hanh: '); readln(th);
  write(tep1,lt:6:1,th:6:1);
end;
close(tep1);
assign(tep2,'E:\b.txt');
rewrite(tep2);reset(tep1);
i:=1;
while not eof(tep1) do
 begin
  read(tep1,lt,th);
  tb:=(lt+th*2)/3;
  writeln('diem trung binh hoc sinh thu ',i,': ',tb:6:1);
  writeln(tep2,'diem trung binh hoc sinh thu ',i,': ',tB:6:1);
  i:=i+1;
 end;
close(tep2);
writeln('nhan enter de ket thuc');
readln;
end.

var xa,xb,xc,ya,yb,yc,a,b,c,s:real;
    DE,CA,VU:BOOLEAN;

FUNCTION kcach(x1,x2,y1,y2:real):real;
begin
  kcach:=sqrt(sqr(x1-x2)+sqr(y1-y2));
end;

FUNCTION dt(a,b,c:real):real;
  var p:real;
begin
  p:=(a+b+c)/2;
  dt:=sqrt(p*(p-a)*(p-b)*(p-c));
end;

FUNCTION kiemtra(a,b,c:real): boolean;
  var ketqua: boolean;
  begin
 ketqua:=False;
 if (a+b>c) and (a+c>b) and (b+c>a) then ketqua:=True;
    kiemtra:=ketqua;
  end;

 PROCEDURE Tinh_chat(a,b,c : real; Var  deu,can,vuong:boolean);
  Begin
Deu:=False;  Can:=false;  Vuong:= False;
  IF  (a=b) or (b=c) or (a=c) then Can:= True;
  if (a=b) and (b=c) then  Deu:=True;
  IF (a*a=b*b+c*c)  OR (b*b=a*a+c*c) OR (c*c=a*a+b*b) Then Vuong:=True;
  end;

BEGIn

 write('nhap toa do dinh A: ' );readln(xa,ya);
 write('nhap toa do dinh B: ');readln(xB,yb);
  write('nhap toa do dinh C: ');readln(xc,yc);
 a:=Kcach(xb,xc,yb,yc);
 b:=kcach(xc,xa,yc,ya);
 c:=kcach(xa,xb,ya,yb);
 if kiemtra(a,b,c) then
 begin
 s:=dt(a,b,c);
 writeln('do dai canh a= ',a:8:2);
 writeln('do dai canh b= ',b:8:2);
  writeln('do dai canh c= ',c:8:2);
 writeln('Chu vi = ',(a+b+c):9:2);
 writeln('dien tich = ',s:9:2);
  tinh_chat(a,b,c,de,ca,vu);
 if de then writeln('DAY LA TAM GIAC DEU ')
  ELSE
  if ca  then writeln('DAY LA TAM GIAC CAN ')
    ELSE
      IF VU then writeln('DAY LA TAM GIAC VUONG ');
        if not(de) and not(ca) and not(vu) then writeln('DAY LA TAM GIAC THUONG ');
 end
 else writeln('khong ton tai tam giac');

readln;
end.