Top 5 Most Common Silly C++ Mistakes

[Null]

I know it seems like a lot of extra typing, but I just prefix all standard library things with std:: instead of using namespace std. I always know what I haven't written myself (part of the standard library), and it makes code easier to read IMHO.

[Mr. Gruntsworthy]

for me, i always use Using Namespace std; i was just taught by the book to do it that way.

[wtd]

Understanding why you do that is more important than knowing how to.

[Mr. Gruntsworthy]

i understand why you use using namespace std;, its because it immediately makes that library available to the whole program if you announce it before or after your #includes, whereas the std:: prefix you have to use before every cout and cin

[wtd]

It doesn't affect whether or not you can use the code in the header. It simply includes the "std" namespace into your program's namespace, such that members of the std namespace declared in any header files that have been included can be used without explicitly denoting the namespace they were declared in.

Consider:

code:

namespace foo {    int bar()    {       return 42;    } } int main() {    cout << foo::bar() << endl; // ok        using foo::bar;             // also ok    cout << bar() << endl;    using namespace foo;        // also ok    cout << bar() << endl; }

[Mr. Gruntsworthy]

well, i think for the sake of simplicity, im going to stick with the way i was taught, until i learn most of the language.

[md]

Mr. Gruntsworthy wrote:

well, i think for the sake of simplicity, im going to stick with the way i was taught, until i learn most of the language.

If your taught something that is wrong and you stick to it you will most likely suffer later on. It's much better to know something is right then simply know it works.

[Mr. Gruntsworthy]

but whats wrong with announcing using namepace for the whole program?

[md]

The same thing with including headers you don't use. The more things you include in your source, and the more things you include in your namespace; the more likely you are to run into nameing collisions. Using std::* instead of using namespace std; also increases readability because it's easy to pick out code that uses the standard libraries (and you really don't need to debug the stl... it's best not to try).

Yes, both ways work; but one is better then the other.

[Mr. Gruntsworthy]

Oh well... back on topic, one of my most common mistakes is spelling errors. Every time i write some code i have to go through it and find errors i made while typing.

[Andy]

okay, this one isnt exactly c++, but it killed me.

when debugging your code, make sure you check every single line, even the obvious ones. forgetting to clear the Z buffer in a d3d application will give you the strangest results.

[Mr. Gruntsworthy]

erm... I dont even know what that is... as ive stated, ive only just started learning C++ a little while ago...

[Clayton]

check your loop's conditions, the difference between a < or a > can be a significant one!

[Mr. Gruntsworthy]

okay, so would

Quote:

while (variable <= 100)

mean that the variable has to be 99 or under to exit the while loop? And what are the other loops[/quote]

[Clayton]

as long as your variable is under 100, that loop will continue to run, so if that condition is true, the loop continues, if it is false, it exits.