List any four software applications which are used by any individual in day to day life. Descri their features.​

1)
var a,b,s:integer;
begin
Readln(a,b);
s:=0;
if (a<0)and(b<0) then
 begin a:=-a; b:=-b; end;
if a<0 then for var i:=1 to b do s+=a
else for var i:=1 to a do s+=b;
WriteLn(s);
end.

Пример:
-7 15
-105

2)
var n,s:integer;
begin
Readln(n);
s:=0;
for var i:=1 to n do s+=i;
WriteLn(s);
end.

Пример:
100
5050

3)
var a,b,s:integer;
begin
Readln(a,b);
s:=0;
for var i:=a to b do s:=s+i*i;
writeLn(s);
end.

Пример:
2 5
54

4)
var a,b,n:integer;
begin
Readln(a,b,n);
for var i:=1 to n do write(random(b-a+1)+a,' ');
end.

Пример:
10 20 5
11 12 14 14 18