Bài 16: Ví dụ làm việc với tệp

program bai_tap;
var t,k:integer;
begin
assign(input,'DULIEU.TXT');
reset(input);
assign(output,'KETQUA.TXT');
rewrite(output);
t:=0;
while not eof(input) do
begin
read(k);
t:=t+sqr(k);
end;
write(t);
close(output);
end.

1,

a, var A: array[1..500] of integer;

i,n:integer;

begin

write(' n la ');readln(n);

for i:=1 to n do

begin

write('a',i,'la'); readln(a[i]);

end;

readln

end.

uses crt;

const fo='b.txt'

var f1:text;

a:array[1..200]of integer;

i,n:integer;

begin

clrscr;

assign(f1,fo); rewrite(f2);

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

for i:=1 to n do

begin

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

end;

for i:=1 to n do

write(f1,a[i]:4);

close(f1);

readln;

end.

program cap_so_cong; 

uses crt; var a: array[1..100] of integer; i, n, k: integer;

{i la bien dem, k de luu cap so} begin clrscr; write('N= ');

readln(n); for i:=1 to n do begin write('A(',i,')= ');

readln(a[i]);

 end; 

{Bat dau phan kiem tra} k:=a[2]-a[1]; i:=2; repeat i:= i+1; until (a[i]<>a[i-1]+k) or (i>n);

 if i>n then write('Day A la mot cap so cong') else

write('Day A khong phai la mot cap so cong');

 readln 

end. 

Program HOC24;

const fi='DL.INP'

fo='DL.OUT'

var s: string;

d,i: byte;

f: text;

procedure ip;

begin

assign(f,fi);

reset(f);

read(f,s);

close(f);

end;

procedure out;

begin

assign(f,fo);

rewrite(f);

d:=0;

for i:=1 to length(s) do if s[i] in ['0'..'9'] then inc(d);

write(f,d);

close(f);

end;

begin

ip;

out;

end.

const fi='dl.inp'

fo='kq.out'

var f1,f2:text;

s:string;

d,i,dem:integer;

begin

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

readln(f1,s);

d:=length(s);

dem:=0;

for i:=1 to d do 

  if s[i] in ['0'..'9'] then inc(dem);

writeln(dem);

readln;

end.

const fi='inp.inp'

       fo='out.inp'

var f1,f2:text;

st:array[1..100]of string;

i,n:integer;

begin

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

n:=0;

while not eof(f1) do 

  begin

n:=n+1;

readln(f1,st[n]);

end;

for i:=1 to n do 

  writeln(f2,length(st[i]));

close(f1);

close(f2);

end.

uses crt;

const fi='hcn.dat'

fo='chuvi.out'

var f1,f2:text;

a,b:array[1..100]of integer;

n,i,j:integer;

begin

clrscr;

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

n:=0;

while not eof(f1) do

begin

n:=n+1;

readln(f1,a[n],b[n]);

end;

for i:=1 to n do

writeln(a[i]*b[i]);

for i:=1 to n do 

  writeln(f2,2*(a[i]+b[i]));

close(f1);

close(f2);

readln;

end.

const fi='data.txt'

fo='tbc.txt'

var f1,f2:text;

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

n,i,t:integer;

begin

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

n:=0;

while not eof(f1) do 

  begin

n:=n+1;

readln(f1,a[n]);

end;

t:=0;

for i:=1 to n do 

  t:=t+a[i];

writeln(f2,t/n:4:2);

close(f1);

close(f2);

end.

Program HOC24;

const fi='cau2.inp'

fo='cau2.out'

var dt,a,b,c: integer;

procedure ip;

begin

assign(f,fi);

reset(f); 

read(f,a,b,c);

close(f);

end;

procedure out;

begin

assign(f,fo);

rewrite(f);

dt:=b*b-4*a*c;

if dt>0 then write(f,'Phuong trinh co 2 nghiem phan biet');

if dt<0 then write(f,'Phuong trinh vo nghiem');

if dt=0 then write(f,'Phuong trinh co 2 nghiem kep');

close(f);

end;

begin

ip;

out;

end.

*Cách khác:

const fi='cau2.inp'

fo='cau2.out'

var f1,f2:text;

a,b,c,delta:real;

begin

assign(f1,fi); reset(f1);

assign(f2,fo); rewrite(f2);

readln(f1,a,b,c);

delta:=sqr(b)-4*a*c;

if delta<0 then writeln(f2,'Phuong trinh vo nghiem');

if delta=0 then writeln(f2,'Phuong trinh co nghiem kep la: ',-b/2*a:4:2);

if delta>0 then 

begin

writeln(f2,'Nghiem thu nhat la: ',(-b-sqrt(delta))/2*a:4:2);

writeln(f2,'Nghiem thu hai la: ',(-b+sqrt(delta))/2*a:4:2);

end;

close(f1);

close(f2);

end.

uk

Bạn nên khai báo biến mảng A là Integer thôi vì exitcode 205 là lỗi tràn số