Analysis of C ++ variable declaration concepts

The C ++ programming language supports various programming languages. Moreover, it has the object-oriented feature. In this article, we will introduce some basic concepts about C ++ variable declaration in detail. You can fully master the relevant knowledge.

• Detailed Usage Guide for C ++ member function pointers
• Overview of the basic content of the C ++ explicit keyword
• Basic concepts of the C ++ include Mechanism
• Summary of the Application Experience of C ++ traversal set
• Detailed description of C ++ assignment function code

Syntax for C ++ variable Declaration: extern int;

Syntax of the function declaration: extern int func1 (int length, int width );

Syntax for variable definition: int;

Function Syntax: int func1 (int length, int width ){}

The following are examples of C ++ variable declaration:

 
 

  
  
//: 02: Declare. cpp
  
  
// Declaration & definition examples
  
  
Extern int I; // variable Declaration
  
  
Extern float f (float); // function declaration
  
  
Float B; // variable description and definition
  
  
Float f (float a) {// Function Definition
  
  
Return a + 1.0;
  
  
}
  
  
Int I; // variable definition
  
  
Int h (int x) {// Function Description and definition
  
  
Return x + 1;
  
  
}
  
  
Int main (){
  
  
B = 1.0;
  
  
I = 2;
  
  
F (B );
  
  
H (I );
  
  
}/**////:~
 
 

C ++ variable declaration extension:

1. What should I declare first? : The Declaration tells the compiler "this function or this variable can be found somewhere and what it looks like ". In fact, all C/C ++ programs require declarations.

2. The definition can also be declaration.

3. extern can be omitted in function declaration.

4. Parameter identifiers are optional during function declaration.

5. In C ++, main () always returns the int type.

The above is an introduction to the C ++ variable declaration.