graff.pas

This ar the basic programs that i did in highschool. From very simple to medium programs. From array

var a:array[1..50,1..50] of integer;
    n,i,j,p,q,u:integer;
    c,viz:array[1..100] of integer;
    f:text;
    ok:boolean;
begin
assign(f,'graf.txt');
reset(f);
readln(f,n);
while not eof(f) do begin
                    readln(f,i,j);
                    a[i,j]:=1;
                    end;
close(f);
c[1]:=1;
viz[1]:=1;
p:=1;
q:=1;
while q<=p do begin
              u:=c[q];
              for i:=1 to n do
                 if ((a[c[q],i]=1) or (a[i,c[q]]=1)) and(viz[i]=0) then begin
                                                                        inc(p);
                                                                        c[p]:=i;
                                                                        viz[i]:=1;
                                                                        end;
              inc(q);
              end;
ok:=true;
for i:=1 to n do
  if viz[i]=0 then ok:=false;
if ok then write('graf conex')
      else write('graful nu e conex');
readln;
end.