1-1/2+1/3-1/4+1/5-1/6.....turbo pascal语言 大家帮个忙！！...

直接写主程序了 定义变量之类lz自己弄吧
begin
readln(n);
s:=0;
for i:=1 to n do
begin
if i mod 2=1 then s:=s+1/i;
if i mod 2=0 then s:=s-1/i;
end;
writeln(s:2:2);
end.
这个是结果用实数表示 保留2位小数的方法

Program David;

Var
i:integer;
total:real;

BEGIN
write('Please input the number of N:');
readln(n); {输入N}
Total:=1.0; {初始化Total}
For i:=2 to n do begin
If i mod 2 = 0 Then {判断是否为奇数}
Total:=Total-1/i
else
Total:=Total+1/i;
end;
writeln(Total);
END.

林斯越那个你是忘记定义n为integer了罢...

program sd;
var i,n:integer;
k:real;
begin
k:=0;
read(n);
for i:=1 to n do
if i mod 2<>0 then k:=k+1/i
else k:=k-1/i;
writeln(k);
end.

program nn;
var
n,i:integer;
s:real;
begin
read(n);
s