how closely does vc++.net 2003 follow ANSI?

At home, I work with visual c++ 6.0 standard.

As a programming beginner, I have already noticed that it does not follow the ANSI standards in several ways.

For example, in the book I'm reading, it says that when you declare a variable in a for loop, it is restricted to that code block, by ANSI standards. However, vc++ 6 doesn't obey this rule, I have noticed.

My friend's dad has visual c++ .net 2003, and I noticed the same thing happens.

This seems weird. On the microsoft website, it said that vc++ 2003 is much more conformative to ANSI...

Is this just one weird example?

Quote:

---

For example, in the book I'm reading, it says that when you declare a variable in a for loop, it is restricted to that code block, by ANSI standards. However, vc++ 6 doesn't obey this rule, I have noticed.

---

Are you sure about that? The following gives me an error with MSVC++ 6.0

Code:

---

int main(void)
{
    for(;;)
        {
                int i = 10;
        }
        i = 12;
}

---

Code:

---

#include <iostream>

int main ()
{

    for ( int loop = 0; loop < 2; loop++ ) {

        std::cout << loop;

    }

    // This compiles and prints '2'
    std::cout << loop;

    return 0;

}

---

MSVC++ 6.0 Pro

hmm..

the exact words of the book are as follows:

"whether a variable is declared within the initialization portion of a for loop is restricted to that loop has changed over time... today, the ansi/iso standard restricts the variable to the scope of the for loop."

i took that to mean that the variable declared in that specific place:

Code:

---

int main(void)
{
    for(int n=5;;)
        {
               
        }
        n=7;
}

---

that seems to work... but the book acts like it shouldn't

edit: yeah, that's what vicious was getting at

MM hmm, I dont think it is supposed to...

You have to turn that feature on in VC2003, it's off by default for backwards compatibility. In the project properties, chose "C++"->"Language" and select "Force Conformance In For Loop Scope".

The compiler switch would be "/Zc:forScope"

Code:

---

        for( int i = 0 ; i < 10 ; i++ )
        {
                printf( "%d\n", i );
        }

        i = -1;

---

error C2065: 'i' : undeclared identifier

brilliant. thank you nvoigt

You can do the same in Visual C++ 6.0 by using the /Za compiler switch.