what is overloading in c++ code example

Example 1: c++ function overload

/*A function over load in c++ is when you take a function with the same definition but change the input variables.
  This can include multiple functions with the same name see below
  */
#include <iostream>
using namespace std;

int function1(int var1){//example of single variable
	//do somthing
}
int function1(int var1,int var2){//of overload
	//do somthing	
}
int function1(int var1,string var3){//of overload
	//do somthing	
}

int main(){
 
  cout << "Hello World" << endl;
  function1(4);
  function1(3,-90);
  function1(34,"it works");//these should all work even tho they have different input variables
  return 0;
}

Example 2: c++ operator overloading

// money.h -- define the prototype
class Money
{
   public:
      Money & operator += (const Money &rhs);
}

// money.cpp -- define the implementation
Money& Money :: operator += (const Money &rhs)
{
   // Yadda Yadda
  
   return *this;
}

Example 3: c++ overload operator

#include <iostream>
using namespace std;

class Box {
   public:
      double getVolume(void) {
         return length * breadth * height;
      }
      void setLength( double len ) {
         length = len;
      }
      void setBreadth( double bre ) {
         breadth = bre;
      }
      void setHeight( double hei ) {
         height = hei;
      }
      
      // Overload + operator to add two Box objects.
      Box operator+(const Box& b) {
         Box box;
         box.length = this->length + b.length;
         box.breadth = this->breadth + b.breadth;
         box.height = this->height + b.height;
         return box;
      }
      
   private:
      double length;      // Length of a box
      double breadth;     // Breadth of a box
      double height;      // Height of a box
};

// Main function for the program
int main() {
   Box Box1;                // Declare Box1 of type Box
   Box Box2;                // Declare Box2 of type Box
   Box Box3;                // Declare Box3 of type Box
   double volume = 0.0;     // Store the volume of a box here
 
   // box 1 specification
   Box1.setLength(6.0); 
   Box1.setBreadth(7.0); 
   Box1.setHeight(5.0);
 
   // box 2 specification
   Box2.setLength(12.0); 
   Box2.setBreadth(13.0); 
   Box2.setHeight(10.0);
 
   // volume of box 1
   volume = Box1.getVolume();
   cout << "Volume of Box1 : " << volume <<endl;
 
   // volume of box 2
   volume = Box2.getVolume();
   cout << "Volume of Box2 : " << volume <<endl;

   // Add two object as follows:
   Box3 = Box1 + Box2;

   // volume of box 3
   volume = Box3.getVolume();
   cout << "Volume of Box3 : " << volume <<endl;

   return 0;
}

Example 4: operator overloading in c++

Box operator+(const Box&);

Example 5: operator ++ overloading c++

class Point
{
public:
	Point& operator++() { ... }		// prefix
	Point operator++(int) { ... }	// postfix
  	friend Point& operator++(Point &p);			// friend prefix
  	friend Point operator++(Point &p, int);		// friend postfix
  	// in Microsoft Docs written "friend Point& operator++(Point &p, int);"
};