var i,s:integer;
function su(a:integer):boolean;
var j:integer;
f:boolean;
begin
f:=true;
for j:=2 to trunc(sqrt(a)) do
if a mod j=0 then f:=false;
su:=f;
end;
begin
s:=0;
for i:=2 to 100 do
if su(i) then s:=s+i;
writeln(s);
end.
var
k,n,i,f,s:longint;
begin
readln(k);
for n:=2 to k do
begin
f:=0;
for i:=2 to n-1 do
if n mod i=0 then
begin
f:=1;
break;
end;
if f=0 then Inc(s,n);
end;
writeln(s);
end.
这是输入k,输出k以内的!最基本的了,很慢。不过100没问题,要快的需要费吗小定了,那个就很难了。
var
n,i,f,s:longint;
begin
for n:=2 to 100 do
begin
f:=0;
for i:=2 to n-1 do
if n mod i=0 then
begin
f:=1;
break;
end;
if f=0 then Inc(s,n);
end;
writeln(s);
end.