1 – All the entities (variables, types, constants, and functions) of the standard C++ library are declared within the std namespace. using namespace std; introduces direct visibility of all the names of the std namespace into the code. ref: http://www.cplusplus.com/doc/tutorial/namespaces/ 2 – Namespaces in C++ are most often used to avoid naming collisions. Although namespaces … Read more
Make sure that Cards::init() is called and returns true before calling Cards::load. The array accessed by Cards::load will consist of three empty strings in case Cards::init() is not called, or if it returns false. 1 solved How to print std::string array with printf in c++? [closed]
Turn on your warnings. You’re missing a return statement here: const std::string get() const { l.get(); } 13 solved Why does this simple C++ code segfault? [closed]
Every #include directive including something from the C++ standard library “loads” the entities into the std namespace (or some other namespace like this). The namespace helps preventing global namespace pollution – by keeping everything in a seperate namespace, identifier collisions are rendered impossible. In the <vector> file, then there is something like namespace std { … Read more
You probably copy pasted functions but forgot to include appropriate headers (newbie mistake). Just try this: #include <iostream> #include <vector> #include <complex> using namespace std; int main() { cout<<“Hello World”; return 0; } 2 solved How to include std::vector, std::complex, std::cout, etc. in Visual Studio C++ [closed]
But it doesn’t works, il only returns 1 and there are at least 2 objects in my map that have same id It’s a std::map. You cannot have two objects with the same key, and I assume you’re trying to use the m_id filed of O as your key. Try using std::multimap instead. And, to … Read more
The error got resolved by @Someprogrammerdude comment about a is_same_v helper variable template defined here. My final code is #ifdef My_OLD_TOOL_CHAIN template< class T, class U > inline constexpr bool is_same_v = std::is_same<T, U>::value; template<class T, class O = T> using IteratorOnly = std::enable_if_t< !is_same_v<typename std::iterator_traits<T>::value_type, void>, O >; #else // My_OLD_TOOL_CHAIN template<class T, class … Read more
As keys in std::map are const your operator< method must be const as well: bool operator<(const RJNodeAddress &l) const // ^ here it should be const anyway as it does not modify the object but in this case missing it leads to compilation errors. solved Creating std::map with a structure as its key and value … Read more
Have you tried: std::string one = “stringa”; std::string two = “stringb”; std::string three = “stringa”; std::string four = “stringb”; if( one == three && two == four ) { return true; } else { return false; } 1 solved My loop condition isn’t being met
The code presented by you in a C++ program. You need to save it in file.cpp format, after that you need to compile with g++ file.cpp and it should work. You have saved it file.c format and compiling it with gcc, which is C standard, not C++. solved can’t understand “std::cout”
Introduction Using the “using namespace std;” statement in C++ is a controversial topic among developers. While it can be a convenient way to access the standard library, it can also lead to confusion and errors. In this article, we will discuss why using namespace std; is considered bad practice and what alternatives are available. We … Read more
Consider two libraries called Foo and Bar: using namespace foo; using namespace bar; Everything works fine, and you can call Blah() from Foo and Quux() from Bar without 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 a conflict: Both Foo … Read more