Bài 14:

program ghep_xau;

uses crt;

var s1,s2,s3,s:string;

begin

       clrscr;

       write('Nhap xau thu nhat: ');  readln(s1);

       write('Nhap xau thu hai: ');  readln(s2);

       write('Nhap xau thu ba: ');   readln(s3);

       s:=concat(s1,s2,s3);

       write('Xau duoc ghep lai la: ',s);

       readln;

end.

Bài 15:

program sao_chep;

uses crt;

var s,st:string;

begin

       clrscr;

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

       st:=copy(s1,1,3);

       write('3 ki tu dau cua xau la: ',st);

       readln;

end.

Bài 14

var a,b,c,d:string;

begin

write('Nhap xau 1: ');readln(a);

write('Nhap xau 2: ');readln(b);

write('Nhap xau 3: ');readln(c);

d:=a+b+c;

writeln(d);

readln

end.

Bài 15

var s:string;

begin

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

writeln(copy(s,1,3));

readln

end.