simple for loop on g++ 4.4.3

["eric lin" <ericlin at fsshl dot zzn dot com>]

dear linux(or g++) user/programer with c++: my name is eric, when I use most current g++ 4.3.3 on ubuntu to test 2 simple c++ programs, one have compiler error,
--------------------
// formore.cpp -- more looping with for

#include <iostream>

using namespace std;

const int ArSize = 16; // example of external declaration

int main()

{

double factorials[ArSize];

factorials[1] = factorials[0] = 1.0;

// int i;

for (int i = 2; i < ArSize; i++)

factorials[i] = i * factorials[i-1];

for (i = 0; i < ArSize; i++)

cout << i << "! = " << factorials[i] << endl;

return 0;

}
--------------------------------------------------------
eric@eric-laptop:~/Documents/c++primerplus/download/ch05$ g++ formore.cpp
formore.cpp: In function ?int main()?:
formore.cpp:12: error: name lookup of ?i? changed for ISO ?for? scoping
formore.cpp:12: note: (if you use ?-fpermissive? G++ will accept your code)
--------------------------
or even more simpler
--------
#include <iostream>
using namespace std;

int main () {



for (int i=0; i<5; i++)
cout << "C++ know loops.\n";

cout << i << endl;


return(0);
}
--------------------
eric@eric-laptop:~$ g++ try.c++
try.c++: In function ?int main()?:
try.c++:11: error: name lookup of ?i? changed for ISO ?for? scoping
try.c++:11: note: (if you use ?-fpermissive? G++ will accept your code)
------------------

--------------------
the other is OK
---------------
// bigstep.cpp -- count as directed

#include <iostream>

int main()

{

using namespace std;

cout << "Enter an integer: ";

int by;

cin >> by;

cout << "Counting by " << by << "s:\n";

for (int i = 0; i < 100; i = i + by)

cout << i << endl;

return 0;

}
-----------------------
eric@eric-laptop:~/Documents/c++primerplus/download/ch05$ g++ bigstep.cpp
eric@eric-laptop:~/Documents/c++primerplus/download/ch05$ ./a.out
------------
  you can see both programs, their for loop are very similar(or the same)
for (int i=0
but why first , and second programs can not compile
but
the third one is OK
?
please advice, thanks in advance your effort and time, fsshl@luxmail.com