追加方式写文件出错
假设 e:\test\test\ 下面有文件

test1.txt
test2.txt
test3.txt

打开文件 test1.txt后，在该目录下产生一个 test1.txt.new文件

然后将test1.txt文件拷贝到test1.txt.new中，源代码是：

var
f,f1:TextFile;
s,s1:string;
begin
opendialog1.Execute();
s:=opendialog1.FileName;

s1:=s+'.new';
AssignFile(f1, s1);
rewrite(f1);
closefile(f1);

AssignFile(f, s);
reset(f);

AssignFile(f1, s);
append(f1); //这句出现错误，请问解决方法，谢谢

readln(f,s);
writeln(f1,s);
closefile(f);
closefile(f1);
end;

[解决办法]
AssignFile(f, s);
reset(f);

AssignFile(f1, s); // AssignFile(f1, s1); 两个s了,应该是s1
append(f1); //这句出现错误，请问解决方法，谢谢
[解决办法]
var
f,f1:TextFile;
s,s1:string;
begin
opendialog1.Execute();
s:=opendialog1.FileName;

s1:=s+'.new';
AssignFile(f1, s1);
rewrite(f1);
closefile(f1);

AssignFile(f, s);
reset(f);

AssignFile(f1, s1);
append(f1);

while not eof(f) do
begin
readln(f,s);
writeln(f1,s);
end;

closefile(f);
closefile(f1);
end;