What are the Different Uses of the Ampersand (&) Symbol in C ?

Understanding the Ampersand (&) Sign in C

The ampersand (&) operator in C serves multiple purposes, including:

1. Taking the Address of a Variable:
   When used before a variable, & returns its memory address. This is commonly used to pass variable addresses to functions or create pointers.
2. Passing Arguments by Reference:
   When an argument is passed to a function using the & symbol, it is passed by reference. This means that any changes made to the argument within the function will be applied to the original variable passed in.
3. Declaring Reference Variables:
   An ampersand can be used to declare reference variables. Reference variables are aliases for existing variables and provide a direct view of the original data. If the referred-to variable is modified, the reference variable will also reflect the changes.
4. Bitwise AND Operator:
   & is also used as a bitwise AND operator, which performs a logical operation on individual bits of two operands. The resulting bits are set to 1 only if both corresponding bits in the operands are 1.

In the example provided:

class CDummy 
{
public:
   int isitme (CDummy& param);
};

int CDummy::isitme (CDummy& param)
{
  if (&param == this)
  { 
       return true; //ampersand sign on left side??
  }
  else 
  {    
       return false;
  }
}

The & sign in ¶m is used to declare a reference variable, meaning that param refers directly to the a object that is passed in. The & before param in the isitme function is the address-of operator, which is being used to compare the address of param with the address of the current object (this). If the addresses are the same, it means that param is referencing the same object as this, and the function returns true.

This example demonstrates the use of the ampersand sign for both reference passing and address comparison, showcasing its versatility in C programming.

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