¡@
c++ Programming Glossary: foowhat is the difference between const int*, const int * const, int const * http://stackoverflow.com/questions/1143262/what-is-the-difference-between-const-int-const-int-const-int-const make sure we are clear on the meaning of const const int foo int const bar note you actually need to set the pointer here.. to set the pointer here because you can't change it later foo is a variable pointer to a constant int. That is you change..
What is an undefined reference/unresolved external symbol error and how do I fix it? http://stackoverflow.com/questions/12573816/what-is-an-undefined-reference-unresolved-external-symbol-error-and-how-do-i-fix of translation is specified by the following phases see footnote . Physical source file characters are mapped in an implementation.. for execution in its execution environment. emphasis mine footnote Implementations must behave as if these separate phases.. to symbolName for gcc . The code struct X virtual void foo struct Y X void foo struct A virtual ~A 0 struct B A virtual..
What is the difference between a definition and a declaration? http://stackoverflow.com/questions/1410563/what-is-the-difference-between-a-definition-and-a-declaration extern can be omitted for function declarations class foo no extern allowed for class declarations A definition actually.. return lhs rhs double f int i double d return i d class foo A definition can be used in the place of a declaration. An identifier..
Why is “using namespace std;” considered bad practice? http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice are using two libraries called Foo and Bar using namespace foo using namespace bar Everything works fine you can call Blah.. the function parameters happen to match. If you have used foo Blah and bar Quux then the introduction of foo Quux would have.. have used foo Blah and bar Quux then the introduction of foo Quux would have been a non event. share improve this answer..
What is the slicing problem in C++? http://stackoverflow.com/questions/274626/what-is-the-slicing-problem-in-c some of it is sliced away. For example class A int foo class B public A int bar So an object of type B has two data.. A int bar So an object of type B has two data members foo and bar Then if you were to write this B b A a b Then the information..
Can a local variable's memory be accessed outside its scope? http://stackoverflow.com/questions/6441218/can-a-local-variables-memory-be-accessed-outside-its-scope accessed outside its scope I have the following code. int foo int a 5 return a int main int p foo cout p p 8 cout p And the.. following code. int foo int a 5 return a int main int p foo cout p p 8 cout p And the code is just running with no runtime.. could be just about to be torn down and replaced with a football stadium and you are going to die in an explosion while..
How to generate a stacktrace when my gcc C++ app crashes http://stackoverflow.com/questions/77005/how-to-generate-a-stacktrace-when-my-gcc-c-app-crashes array size STDERR_FILENO exit 1 void baz int foo int 1 make a bad pointer printf d n foo causes segfault void.. 1 void baz int foo int 1 make a bad pointer printf d n foo causes segfault void bar baz void foo bar int main int argc.. pointer printf d n foo causes segfault void bar baz void foo bar int main int argc char argv signal SIGSEGV handler install..
Why is “using namespace std;” considered bad practice? http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-bad-practice all. But consider this You are using two libraries called Foo and Bar using namespace foo using namespace bar Everything works.. namespace bar Everything works fine you can call Blah from Foo and Quux from Bar without problems. But one day you upgrade.. problems. But one day you upgrade to a new version of Foo 2.0 which now offers a function called Quux . Now you've got..
What is this weird colon-member syntax in the constructor? http://stackoverflow.com/questions/1711990/what-is-this-weird-colon-member-syntax-in-the-constructor seen an example like the following #include iostream class Foo public int bar Foo int num bar num int main void std cout Foo.. the following #include iostream class Foo public int bar Foo int num bar num int main void std cout Foo 42 .bar std endl.. public int bar Foo int num bar num int main void std cout Foo 42 .bar std endl return 0 What does this strange bar num mean..
Is there a performance difference between i++ and ++i in C++? http://stackoverflow.com/questions/24901/is-there-a-performance-difference-between-i-and-i-in-c functions. Here's a standard pair of these functions Foo Foo operator called for i this data 1 return this Foo Foo operator.. functions. Here's a standard pair of these functions Foo Foo operator called for i this data 1 return this Foo Foo operator.. Foo Foo operator called for i this data 1 return this Foo Foo operator int ignored_dummy_value called for i Foo tmp this..
Why can templates only be implemented in the header file? http://stackoverflow.com/questions/495021/why-can-templates-only-be-implemented-in-the-header-file template argument. For example template typename T struct Foo T bar void doSomething T param do stuff using T somewhere in.. doSomething T param do stuff using T somewhere in a .cpp Foo int f When reading this line the compiler will create a new.. line the compiler will create a new class let's call it FooInt which is equivalent to the following struct FooInt int bar..
When to use forward declaration? http://stackoverflow.com/questions/553682/when-to-use-forward-declaration be a pointer or a reference to the incomplete type class Foo X pt X pt Declare functions or methods which accept return incomplete.. do with an incomplete type Use it as a base class class Foo X compiler error Use it to declare a member class Foo X m compiler.. Foo X compiler error Use it to declare a member class Foo X m compiler error Define functions or methods using this type..
Converting a pointer into an integer http://stackoverflow.com/questions/153065/converting-a-pointer-into-an-integer short example void function MESSAGE_ID id void param if id FOO int real_param int param ... Of course on a 64 bit machine I..
Do-While and if-else statements in C/C++ macros http://stackoverflow.com/questions/154136/do-while-and-if-else-statements-in-c-c-macros a meaningless do while loop. Here are examples. #define FOO X do f X g X while 0 #define FOO X if 1 f X g X else I can't.. are examples. #define FOO X do f X g X while 0 #define FOO X if 1 f X g X else I can't see what the do while is doing... while is doing. Why not just write this without it #define FOO X f X g X c c macros c faq share improve this question ..
Why must I put a semicolon at the end of class declaration in C++? http://stackoverflow.com/questions/1783465/why-must-i-put-a-semicolon-at-the-end-of-class-declaration-in-c separated list of instances of the class. Example class FOO int bar int baz waldo declares both the class FOO and an object.. class FOO int bar int baz waldo declares both the class FOO and an object waldo. The instance sequence may be empty in which.. may be empty in which case you would have just class FOO int bar int baz You have to put the semicolon there so the compiler..
Header guards do not seem to work? http://stackoverflow.com/questions/18579340/header-guards-do-not-seem-to-work memory a .i file for intermediate foo.cpp #include foo1.h FOO #include foo2.h foo1.h extern C int puts const char #define.. foo2.h foo1.h extern C int puts const char #define FOO int main foo2.h puts Hello world n Compile with g Wall E o foo.i..
Is there a simple script to convert C++ enum to string? http://stackoverflow.com/questions/201593/is-there-a-simple-script-to-convert-c-enum-to-string to string Suppose we have some named enums enum MyEnum FOO BAR 0x50 What I googled for is a script any language that scans.. like this char enum_to_string MyEnum t switch t case FOO return FOO case BAR return BAR default return INVALID ENUM .. this char enum_to_string MyEnum t switch t case FOO return FOO case BAR return BAR default return INVALID ENUM The gotcha..
http://stackoverflow.com/questions/2506167/c-macros-with-memory to define macros write_foo A and read_foo so that WRITE_FOO hello code_block_1 READ_FOO code_block_2 READ_FOO WRITE_FOO.. A and read_foo so that WRITE_FOO hello code_block_1 READ_FOO code_block_2 READ_FOO WRITE_FOO world code_block_3 READ_FOO.. WRITE_FOO hello code_block_1 READ_FOO code_block_2 READ_FOO WRITE_FOO world code_block_3 READ_FOO code_block_4 READ_FOO..
|