1 Answer. The error you offer, error: expected initializer before ‘namespace’ suggests that there is a structure or variable declaration that isn’t terminated. Something like: … Here, the ‘struct foo’ declaration isn’t terminated with a semicolon.
Similarly, Why should we use using namespace std in C++?
So when we run a program to print something, “using namespace std” says if you find something that is not declared in the current scope go and check std. using namespace std; are used. It is because computer needs to know the code for the cout, cin functionalities and it needs to know which namespace they are defined.
Additionally, What is expected unqualified ID before if? The error is occurring because you have 2 if statements outside of a function. You could move them into the ping() function which would fix the error but there seems to be a logic error with the 2 if statements as well.
What is an initializer in Arduino code?
The member initializer list is specified after the arguments of the constructor. It begins with a colon followed by the name of each variable to initialize, separated by commas [1]. The value to assign to each data member is specified between parenthesis after the name of each data member of the list.
What is an initializer in C++?
The initializer list is used to directly initialize data members of a class. … The list begins with a colon ( : ) and is followed by the list of variables that are to be initialized – all of the variables are separated by a comma with their values in curly brackets.
Why is namespace used?
A namespace is a declarative region that provides a scope to the identifiers (the names of types, functions, variables, etc) inside it. Namespaces are used to organize code into logical groups and to prevent name collisions that can occur especially when your code base includes multiple libraries.
Should you use namespace?
Namespace usings are for your convenience, not for you to inflict on others: Never write a using declaration or a using directive before an #include directive. Corollary: In header files, don’t write namespace-level using directives or using declarations; instead, explicitly namespace-qualify all names.
What is the meaning of using namespace std?
The using namespace statement just means that in the scope it is present, make all the things under the std namespace available without having to prefix std:: before each of them.
What is an unqualified ID in C++?
A qualified name is one that has some sort of indication of where it belongs, e.g. a class specification, namespace specification, etc. An unqualified name is one that isn’t qualified.
What is not declared in this scope error Arduino?
In case of getting the Serial1 was not declared in this scope error, chances are your Arduino has no Serial1. Assuming that you use Arduino Uno, you need to comment the Serial1 and un-comment the SoftwareSerial part in order to solve the problem.
What is an initializer in programming?
In computer programming, initialization (or initialisation) is the assignment of an initial value for a data object or variable. … Programming constructs which perform initialization are typically called initializers and initializer lists.
What is declaration and initialization in C?
Declaration tells the compiler about the existence of an entity in the program and its location. When you declare a variable, you should also initialize it. Initialization is the process of assigning a value to the Variable.
How structures are initialized in C?
Structure members can be initialized using curly braces ‘{}’. For example, following is a valid initialization. // gets value 1. The order of declaration is followed.
What is the primary purpose of a namespace?
In computer programming, namespaces are typically employed for the purpose of grouping symbols and identifiers around a particular functionality and to avoid name collisions between multiple identifiers that share the same name.
What is the purpose of namespace Mcq?
Explanation: Namespace allows you to group class, objects, and functions. It is used to divide the global scope into the sub-scopes.
What is the use of namespace in C#?
In C#, namespaces are used to logically arrange classes, structs, interfaces, enums and delegates. The namespaces in C# can be nested. That means one namespace can contain other namespaces also. In C#, namespaces are used to logically arrange classes, structs, interfaces, enums and delegates.
Is it good to use using namespace std?
The statement using namespace std is generally considered bad practice. The alternative to this statement is to specify the namespace to which the identifier belongs using the scope operator(::) each time we declare a type. Example 1: CPP.
Why we should not use using namespace std?
While this practice is okay for example code, pulling in the entire std namespace into the global namespace is not good as it defeats the purpose of namespaces and can lead to name collisions. This situation is called namespace pollution.
What can I use instead of namespace std?
The main alternatives to bringing in everything from the std namespace into the global one with using namespace std; at global scope are: Only bring in the actual names you need. For example just bring in vector with using std::vector; Always use explicit namespace qualifications when you use a name.
What is std namespace?
It is known that “std” (abbreviation for the standard) is a namespace whose members are used in the program. So the members of the “std” namespace are cout, cin, endl, etc. This namespace is present in the iostream.
What does std :: mean in C++?
Basically STD is short for standard (in c++ only. If your doctor mentions it it’s definitely not standard) and it’s just a set of data types and commands prepackaged with the language. The reason you have to include them is because they’re actually .c and .h files tucked into the compiler.
What is namespace example?
In computing, a namespace is a set of signs (names) that are used to identify and refer to objects of various kinds. … Prominent examples for namespaces include file systems, which assign names to files. Some programming languages organize their variables and subroutines in namespaces.
What do you mean by unqualified id?
A qualified name is one that has some sort of indication of where it belongs, e.g. a class specification, namespace specification, etc. An unqualified name is one that isn’t qualified. … ::A is a qualified-id but has no nested-name-specifier.
What is qualified id?
A qualified identifier, in C#, is a string that includes a single identifier or a sequence of identifiers that are separated by dot (.). … It enables two identifiers that have a common name and are declared within two different nested name spaces.
What does undeclared identifier mean in C++?
The identifier is undeclared
If the identifier is a variable or a function name, you must declare it before it can be used. … If the identifier is the tag for a user-defined type, for example, a class or struct , the type of the tag must be declared before it can be used.