A reference to C+

The reference to the C+

The C++ reference vs pointer

References can easily be confused with pointers, and there are three main differences between them:

• There are no empty references. The reference must be connected to a piece of legitimate memory.
• Once a reference is initialized as an object, it cannot be directed to another object. The pointer can point to another object at any time.
• References must be initialized at the time they are created. The pointer can be initialized at any time.

Create a reference in C+

Imagine that the variable name is a label that the variable is attached to the memory location, and you can think of the reference as a second label that the variable is attached to the memory location. T herefore, you can access the contents of the variable by name or reference of the original variable. For example:

int    i = 17;

We can declare a reference variable for i, as follows:

int&    r = i;

In these statements, read as a reference. T herefore, the first declaration can read "r is an integer reference that initializes to i" and the second declaration can read "s is a double reference that initializes to d". The following example uses int and double references:

#include <iostream>
 
using namespace std;
 
int main ()
{
   // 声明简单的变量
   int    i;
   double d;
 
   // 声明引用变量
   int&    r = i;
   double& s = d;
   
   i = 5;
   cout << "Value of i : " << i << endl;
   cout << "Value of i reference : " << r  << endl;
 
   d = 11.7;
   cout << "Value of d : " << d << endl;
   cout << "Value of d reference : " << s  << endl;
   
   return 0;
}

When the above code is compiled and executed, it produces the following results:

Value of i : 5
Value of i reference : 5
Value of d : 11.7
Value of d reference : 11.7

References are typically used for function argument lists and function return values. Here are two important concepts related to C++ references that C?programmers must be aware of: