Cấu trúc rẽ nhánh:

1/ 

uses crt;
var n:integer;
begin
   clrscr;
   write('Nhap n: '); readln(n);
   if n>0 then writeln(n,' la so duong')
   else if n<0 then writeln(n,' la so am')
   else writeln(n,' la so khong');
   readln
end.

2/

uses crt;
var a,b:real;
begin
clrscr;
   write('Nhap a: '); readln(a);
   write('Nhap b: '); readln(b);
   if a>b then writeln(a:4:2,' lon hon ',b:4:2)
   else if a<b then writeln(b:4:2,' lon hon ',a:4:2)
   else writeln(a:4:2,' bang ',b:4:2);
   readln
end.

3/ 

uses crt;
var a,b,c:real;
begin
   clrscr;
   write('Nhap a: '); readln(a);
   write ('Nhap b: '); readln(b);
   write('Nhap c: '); readln(c);
   if ((a+b)>c) and ((b+c)>a) and ((a+c)>b) then
   writeln(a:4:2,',',b:4:2,',',c:4:2, ' la ba canh cua tam giac')
   else
   writeln(a:4:2,',',b:4:2,',',c:4:2, ' khong phai la ba canh cua tam giac');
   readln
end.

4/

uses crt;
var a:integer;
begin
   clrscr;
   write('Nhap mot so: '); readln(a);
   if a mod 2 = 0 then writeln(a,' la so chan')
   else writeln(a,' la so le');
   readln
end.

Cấu trúc tuần tự:

1/

uses crt;
var a,b:real;
begin 
   clrscr;
   write('Nhap a: '); readln(a);
   write('Nhap b: '); readln(b);
   writeln('Tong cua hai so la: ',a+b:4:2);
   readln
end.

2/ 

uses crt;
const pi=3.14;
var r,dt,cv:real;
begin
   clrscr;
   write('Nhap ban kinh: '); readln(r);
   cv:=2*r*pi;
   writeln('Chu vi la: ',cv:4:2);
   dt:=sqr(r)*pi;
   writeln('Dien tich la: ',dt:4:2);
   readln
end.

3/

uses crt;
var dai,rong,cv,dt:real;
begin
   clrscr;
   write('Nhap chieu dai: '); readln(dai);
   write('Nhap chieu rong: '); readln(rong);
   cv:=(dai+rong)*2;
   writeln('Chu vi la: ',cv:4:2);
   dt:=dai*rong;
   writeln('Dien tich la: ',dt:4:2);
    readln
end.

Cấu trúc rẽ nhánh

Bài 1: 

uses crt;

var n:integer;

begin

clrscr;

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

if n>0 then writeln(n,' la so duong')

else if n<0 then writeln(n,' la so am')

else writeln(n,' la so khong');

readln;

end.

Bài 2: 

uses crt;

var a,b:real;

begin

clrscr;

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

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

if a>b then writeln(a:4:2,' lon hon ',b:4:2)

else if a<b then writeln(b:4:2,' lon hon ',a:4:2)

else writeln(a:4:2,' bang ',b:4:2);

readln;

end.

Bài 3: 

uses crt;

var a,b,c: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) then

   begin

        if (a+b>c) and (a+c>b) and (b+c>a) then writeln('Day la ba canh trong mot tam giac')

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

end

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

readln;

end.

Bài 4: 

uses crt;

var a:integer;

begin

clrscr;

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

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

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

readln;

end.

Câu trúc tuần tự

Bài 1: 

uses crt;

var a,b:real;

begin 

clrscr;

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

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

writeln('Tong cua hai so la: ',a+b:4:2);

readln;

end.

Bài 2: 

uses crt;

var r,dt,cv:real;

begin

clrscr;

repeat

write('Ban kinh='); readln(r);

until r>0;

cv:=2*r*pi;

writeln('Chu vi=',cv:4:2);

dt:=sqr(r)*pi;

writeln('Dien tich=',dt:4:2);

readln;

end.

Bài 3: 

uses crt;

var dai,rong,cv,dt:real;

begin

clrscr;

repeat

write('Chieu dai='); readln(dai);

write('Chieu rong='); readln(rong);

until (dai>0) and (rong>0) and (dai>=rong);

cv:=(dai+rong)*2;

writeln('Chu vi=',cv:4:2);

dt:=dai*rong;

writeln('Dien tich=',dt:4:2);

readln;

end.