uses crt;

var a:array[1..100]of integer;

i,n,dem,t,tb:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

dem:=0;

t:=0;

for i:=1 to n do 

  if a[i]>0 then

begin

dem:=dem+1;

t:=t+a[i];

end;

writeln('So luong phan tu duong la: ',dem);

writeln('Tong cac phan tu duong la: ',t);

writeln('Trung binh cac phan tu duong la: ',t/dem:4:2);

readln;

end.

đúng không đây ạ

Bài 1: 

uses crt;

var a:array[1..100]of integer;

i,n,kt,max,x,j,tam:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

  begin

write('A[',i,']='); readln(a[i]);

end;

writeln('Mang ban vua nhap la: ');

for i:=1 to n do 

  write(a[i]:4);

writeln;

for i:=1 to n-1 do 

  for j:=i+1 to n do 

if a[i]>a[j] then 

begin

tam:=a[i];

a[i]:=a[j];

a[j]:=tam;

end;

writeln('Day tang dan la: ');

for i:=1 to n do 

  write(a[i]:4);

writeln;

write('Nhap x='); readln(x);

max:=0;

kt:=0;

for i:=1 to n do 

  if (a[i] mod 2=0) and (a[i]<=x) then 

   begin

  if max<a[i] then max:=a[i];

kt:=1;

end;

if kt=0 then writeln('Trong day khong co so le')

else writeln('So chan lon nhat khong vuot qua ',x,' la: ',max);

readln;

end.

Mình chỉ viết chương trình chính thôi, còn chương trình con bạn tự viết nhé

uses crt;

var a:array[1..100]of integer;

i,n,t,t1,t2:integer;

begin

clrscr;

write('Nhap n='); readln(n);

for i:=1 to n do 

 begin

write('A[',i,']='); readln(a[i]);

edn;

t:=0;

for i:=1 to n do 

 t:=t+a[i];

writeln(t);

readln;

end.

uses crt;

var a,b,c,p,s,am,bn,cp:real;

begin

clrscr;

write('Nhap a='); readln(a);

write('Nhap b='); readln(b);

write('Nhap c='); readln(c);

if (a>0) and (b>0) and (c>0) and (a+b>c) and (a+c>b) and (b+c>a) then

begin

writeln('Day la ba canh trong mot tam giac vuong');

p:=(a+b+c)/2;

s:=sqrt(p*(p-a)*(p-b)*(p-c));

writeln('Dien tich tam giac la: ',s:4:2);

am:=sqrt(2*(sqr(b)+sqr(c))-sqr(a))/4;

bn:=sqrt(2*(sqr(a)+sqr(c))-sqr(b))/4;

cp:=sqrt(2*(sqr(a)+sqr(b))-sqr(c))/4;

writeln('Do dai duong trung tuyen ung voi canh a la: ',am:4:2);

writeln('Do dai duong trung tuyen ung voi canh b la: ',bn:4:2);

writeln('Do dai duong trung tuyen ung voi canh c la: ',cp:4:2);

end

else writeln('Day khong la ba canh trong mot tam giac');

readln;

end.

uses crt;
var a,b,c:integer;
{-----------------------------chuong-trinh-con----------------------------}
procedure hoandoi(var x,y:integer);
var tam:integer;
begin
tam:=x;
x:=y;
y:=tam;
end;
{-----------------------------chuong-trinh-chinh----------------------------}
begin
clrscr;
write('Nhap a='); readln(a);
write('Nhap b='); readln(b);
write('Nhap c='); readln(c);
if a>b then hoandoi(a,b)
else if b>c then hoandoi(b,c);
writeln(a,' ',b,' ',c);
readln;
end.