C I/O occurs in streams, which are sequences of bytes. If bytes flow from a device like a keyboard, a disk drive, or a network connection etc. To main memory, this is called input operation and if bytes flow from main memory to a device like a display screen, a printer, a disk drive, or a network connection, etc., this is called output operation. Standard output stream (cout) The cout is a predefined object of ostream class. It is connected with the standard output device, which is usually a display screen. The cout is used in conjunction with stream insertion operator (cout).

C Basic Input/Output. C I/O operation is using the stream concept. Stream is the sequence of bytes or flow of data. It makes the performance fast. If bytes flow from main memory to device like printer, display screen, or a network connection, etc, this is called as output operation. In the Problems View you can distinguish between compiler and code analyzer errors via the column problem type. In the editor there are different icons. But back to your problem. In your case it is a false warning. The code analyzer (CODAN) does not recognize the symbol 'cout' because it does not find the system includes (iostream). Cause & Solution C provides many standard operations like cout, cin and many more. If you have to make use or define anything standard then you have to use the syntax std:: then the name of the operation you want to have.

Hello. I am having difficulty trying to use the ByteBuffer lib. http://siggiorn.com/arduino-circular-byte-buffer/. I am sure it is something simple, and am hoping you can give me a hint…

I downloaded the .zip file, opened it and copied all the contained files into a subdirectoy named “ArduinoByteBuffer” in the …MyDocumentsArduinolibraries directory. (WinXP, Arduino 1.0.3)

Dev C 2b 2b Cout Does Not Name A Type 2

I then try to compile the example sketch, but get the following error: “ByteBufferExample:8: error: ‘ByteBuffer’ does not name a type”

Here is the sample code (included with the Lib):

And here is the entire list of error messages I get:

ByteBufferExample:8: error: ‘ByteBuffer’ does not name a type
ByteBufferExample.pde: In function ‘void setup()’:
ByteBufferExample:13: error: ‘buffer’ was not declared in this scope
ByteBufferExample.pde: In function ‘void loop()’:
ByteBufferExample:25: error: ‘buffer’ was not declared in this scope
ByteBufferExample:35: error: ‘buffer’ was not declared in this scope

I tried changing #include <ByteBuffer.h> to #include “ByteBuffer.h”, that did not help. I also tried moving the ByteBuffer lib into the c:programarduino… directory, again did not help.

I am sure this is something simple, and would appreciate any pointers.

In C++, a function must be declared and defined before it is used (called) anywhere in the program.

C++ Function Prototype

A function prototype is a declaration of the function that tells the program about the type of the value returned by the function and the number and type of arguments.

Dev C%2b%2b Cout Does Not Name A Type

Function prototyping is one very useful feature of C++ function. A function prototype describes the function interface to the compiler by giving details such as the number and type of arguments and the type of return values.

The prototype declaration looks just like a function definition except that it has no body i.e., its code is missing. This is the time you knew the difference between a declaration and a definition.

A declaration introduces a (function) name to the program whereas a definition is a declaration that also tells the program what the function is doing and how it is doing.

Thus the above given examples are function definitions and the following are declarations or shall we say, function prototypes :

Therefore, you can say that a function prototype has the following parts :

return type
name of the function
argument list

Let's look at the following function prototype :

Here,

return type - int
name of the function - sum
argument list - (int n1, int n2)

Dev C 2b 2b Cout Does Not Name A Type B

Since every function prototype is followed by a semicolon, so at last there will be ; as in the above function prototype.

Tip - A function declaration can skip the argument names but a function definition, can not.

Use of Void

As you know about void data type that it specifies an empty set of values and it is used as the return type for functions that do not return a value. Thus, a function that does not return a value is declared as follows:

By declaring a function's return type void, one makes sure that the function cannot be used in an assignment statement.

Tip - If a function does not return a result, declare the result type as void.

A function that does not require any parameter (i.e., it has an empty argument list) can be declared as follows:

Tip - If a function takes no argument, you should specify void in its prototype.

As already mentioned if you omit the type specifier of a function, it is assumed to be returning int values. For the functions returning non-integer values, the type specifier must be given.

A function prototype can either appear before the definition of calling the function (such prototypes are known as a global prototypes) or within the definition of calling function (such prototypes are known as local prototypes). The global and local prototypes have been described in separate tutorial, in C++ Scope Rules tutorial.

C++ Function Definition

The general form of a function definition is as given below:

Here, the return_type specifies the type of value that the return statement of the functions returns. It may be any valid C++ data type. If no type is specified, the compiler assumes that the function returns an integer value. The parameter list is a common-separated list of variables of a function referred to as its arguments. A function may be without any parameters, in which case, the parameter list is empty. Here are some examples of functions. Below is a function having only one parameter of int type and return type also as int :

Here is another function definition example. This function has return type as int, and have two integer parameters

From the above examples it is clear now that the parameter declaration list for a function takes this general form :

A C++ function can also have an 'open' parameter list i.e., it can have any number as follows :

C++ Function Prototype & Function Definition Example

Let's take an example program, demonstrating function prototype and function definition in C++. This program also uses function calling, which is covered in C++ Calling Function tutorial coming in the next chapter.

Below are the two sample run of this C++ program:

Here is another example, also demonstrating function prototype and function definition in C++. This program uses return_type as void

Here is the sample run of the above C++ program:

Let's take one more example program for the complete understanding on C++ function prototype and function definition

Below is the sample run of the above C++ program: