Variables in C++ code example

Example 1: declare variable c++

#include <iostream>
using namespace std;

int main(){
   	int numero; //il tipo della variabile è int, il nome della variabile è 'numero'
}

Example 2: c++ declare variable

std::string str = "text";	// stores a string
int    foo = 3;				// stores any integer
float  bar = 3.14;			// stores 32 bit number
double baz = 3.14159265;	// stores 64 bit number

Example 3: variabvles in c++

#include <iostream>

using namespace std
  
int main{
	int x = 3;
    float g = 4.0;
    long h = 1234567;
    double j = 1237886.099;
    cout<<x<<endl;
    cout<<h<<endl;
    cout<<g<<endl;
    cout<<j<<endl;
}

Example 4: C++ variables

Create a variable called myNum of type int and assign it the value 15:
  int myNum = 15;
cout << myNum;

Example 5: constant variables in c++

// various versions of const are explained below
#include <iostream>
class Entity {
private:
	int m_X, m_Y;
	mutable int var; // can be modified inside const menthods
	int* m_x, *m_y;// * use to create pointer in one line
public:
	int GetX() const // cant modify class variables
	{
		//m_X = 4;//error private member can't be modified inside const method
		var = 5; // was set mutable
		return m_X;
	}
	int Get_X()// will modify class 
	{
		return m_X;
	}
	const int* const getX() const  // returning a pointer that cannot be modified & context of pointer cannot be modified
	{
		//m_x = 4;
		return m_x;
	}
	void PrintEntity(const Entity& e) {
		std::cout << e.GetX() << std::endl;
	}
};
int main() {
	Entity e;
	const int MAX_AGE = 90;
   // MAX_AGE =100; error const var is stored in read only section in memory and we can't write to that memory
	//  int const* a = new int; is same as const int* a = new int ;////but you can't change the context of pointer but can reassign it to a pointer something else
	int * const a = new int; //can change the context of pointer but can't reassign it to a pointer something else
   *a = 2;
    a = &MAX_AGE;// error can't change it to ptr something else
   	std::cout << *a << std::endl;
	a =(int*) &MAX_AGE;
	std::cout << *a << std::endl;
}

Example 6: C++ Variable

#include <iostream>
using namespace std;
int main(){
	
int number = 1;              
double decimal = 6.9;    
char characterx = 'i';   
string text ="Sup";     
bool boolean = true;      

return 0;
}