Program prog1;Uses crt;var a: array [1..50] of integer; k, i: integer;beginclrscr; randomize;for i:=1 to 50 dobegina[i]:= random(41);write(a[i],' ');if a[i]=23 then inc(k);end;writeln;writeln; writeln('k = ',k);end.Program prog2;Uses crt;var a: array [1..50] of integer; i: integer;beginclrscr; randomize;for i:=1 to 50 dobegina[i]:= random(41);write(a[i],' ');if (a[i] mod 5) =0 then a[i]:=-1;end;writeln;writeln;for i:=1 to 50 dowrite(a[i],' ');end.Program prog3;Uses crt;var a: array [1..10] of integer; tmp, i: integer;beginclrscr; randomize;for i:=1 to 10 dobegina[i]:= random(41);write(a[i],' ');end;tmp:=a[2];a[2]:=a[9];a[9]:=tmp;writeln;writeln;for i:=1 to 10 dowrite(a[i],' ');end.Program prog4;Uses crt;var a: array [1..100] of integer; n, i,k: integer;beginclrscr; randomize;write('N = ');readln(n);for i:=1 to n dobegina[i]:= random(41);write(a[i],' ');end;writeln;writeln;for i:=1 to n-1 doif ((a[i] mod 10)=2)and((a[i+1] mod 10)=2) then inc(k);writeln('k = ', k);end.