1:

uses crt;

const fi='ketqua.txt'

var f1:text;

st:string;

i,d:integer;

begin

clrscr;

assign(f1,fi); rewrite(f1);

write('Nhap xau:'); readln(st);

d:=length(st);

for i:=1 to d do 

 if st[i]=#32 then delete(st,i,1);

writeln(f1,st);

close(f1);

end.

2:

uses crt;

var a,b,c,d:integer;

{----------chuong-trinh-con-----------------------}

function min(x,y:integer):integer;

begin

if x<y then min:=x

else min:=y;

end;

{---------------chuong-trinh-chinh--------------------}

begin

clrscr;

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

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

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

write('d='); readln(d);

writeln(min(a,min(b,min(c,d))));

readln;

end.

cau 1:

uses crt;

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

n,i,min: integer;

begin

readln(n);

for i:=1 to n do

readln(a[i]);

min:=a[1];

for i:=2 to n do

if min>a[i] then min=a[i];

writeln(a[i]);

readln;

end.

cau 2:

uses crt;

g:text;

s:string;

const fo='CHUSO.TXT'

begin

assign(g,fo);

rewrite(g);

readln(s);

for i:=1 to length(s) do

if not((s[i] in ['a'..'z'])and(s[i] in ['A'..'Z])) then delete(s,i,1);

writeln(g,s);

end.

uses crt;

var m:integer;

begin

clrscr;

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

if m mod 2=0 then writeln(m,' la so chan')

else writeln(m,' la so le');

writeln('Binh phuong cua ',m,' la: ',sqr(m));

writeln('Can bac hai cua ',m,' la: ',sqrt(m));

writeln('Gia tri tuyet doi cua ',m,' la: ',abs(m));

readln;

end.

#include <bits/stdc++.h>

using namespace std;

long long x,y;

int main()

{

cin>>x>>y;

freopen("kq.txt","w",stdout);

cout<<x+y<<endl;

cout<<x-y<<endl;

cout<<x*y<<endl;

cout<<fixed<<setprecision(2)<<(x*1.0)/(y*1.0);

return 0;

}

Bài 3: 

uses crt;

const fi='teptong.txt'

var a,b:integer;

f1:text;

begin

clrscr;

assign(f1,fi); rewrite(f1);

readln(a,b);

writeln(a+b);

writeln(f1,a+b);

close(f1);

readln;

end.

C1:

khai báo:

      program  hieu_a_va_b   ("tự đặt tên cái này ko cần thiết)

      uses crt;

      var a, b : integer

phần thân:

       begin

            writeln ("nhap so a");  read(a);

            writeln ("nhap so b");  read(b);

             writeln ("hieu cua hai so la: a - b=" , a - b);

        end.

C2:

khai báo:

      program    tinh_ba_so

      uses crt;

      var a, b, c : integer

phần thân:

       begin

            writeln ("nhap so a");  read(a);

            writeln ("nhap so b");  read(b);

            writeln ("nhap so c");  read(c);

             writeln ("ket qua cua phep tinh a+b-c la" , a+b-c);

        end.

C3:

khai báo:

      program    tinh_ba_so

      uses crt;

      var x, y, z : integer

phần thân:

       begin

            writeln ("nhap so x");  read(x);

            writeln ("nhap so y");  read(y);

            writeln ("nhap so z");  read(z);

             writeln ("ket qua cua phep tinh (x+y)*z la") , (x+y)*z);

        end.

nhớ chạy thử chương trình nha. xem có lỗi ko.

(nhớ tick cho mk nha)

Câu 2: 

#include <bits/stdc++.h>

using namespace std;

long long a,b;

int main()

{

cin>>a>>b;

cout<<a-b;

return 0;

}