Bµi 1: Program xau; var s:string; i:Byte; Begin Write('Moi nhap xau: '); Readln(s); Writeln('Xau vua nhap: ',s); Write('Xau nguoc lai: '); For i:=length(s) downto 1 do write(s[i]); Readln; End. Bµi 2: Program mang2chieu; Var A:array[1 10,1 10] of integer; Max:integer; N,i,j: Byte; Begin Write('Moi nhap N='); Readln(N); Writeln('Moi nhap cac phan tu mang:'); For i:=1 to N do For j:=1 to N do Begin write('A[',i,',',j,',',']'); readln(A[i,j]) End; Max:=A[1,1]; Write('Cac phan tu tren duong cheo chinh: '); For i:=1 to N do For j:=1 to N do Begin if i=j then write(a[i,j],' '); if Max<A[i,j] then Max:=A[i,j]; end; Writeln; Writeln('Gia tri lon nhat= ',Max); Write('Vi tri: '); For i:=1 to N do For j:=1 to N do If A[i,j]=Max then write('(',i,',',j,')'); Readln End. Bµi 3: Program Mang1chieu; Var A:array[1 50] of integer; S:integer; N,i,dau, cuoi: Byte; Begin Write('Moi nhap N='); Readln(N); Writeln('Moi nhap cac phan tu mang:'); For i:=1 to N do Begin write('A[',i,']='); readln(A[i]) ; End; S:=0; i:=1; While A[i]<>0 do i:=i+1; Dau:=i; i:=N; While A[i]<>0 do i:=i-1; Cuoi:=i; For i:=dau to cuoi do S:=S+A[i]; Writeln('Tong cac so giua 2 so 0= ',S); Readln End. Bµi 4: Program So_hoan_thien; Var R,S,i,j,d:Word; T:Word; Begin Write('Moi nhap R, S:'); Readln(R,S); Write('Cac so hoan thien: '); d:=0; For i:=R to S do Begin T:=0; For j:=1 to i-1 do if i mod j=0 then T:=T+j; if T=i then Begin d:=d+1; write(i,' '); end; End; If d=0 then Write('khong tim thay'); Readln; End. . Write('Moi nhap N='); Readln(N); Writeln('Moi nhap cac phan tu mang:'); For i:=1 to N do For j:=1 to N do Begin write('A[',i,',',j,',',']');. Write('Moi nhap N='); Readln(N); Writeln('Moi nhap cac phan tu mang:'); For i:=1 to N do Begin write('A[',i,']=');