CPP

and c++

#include<iostream>
using namespace std;
int main(){
	int a;
	cin>>a;
	if(a >= 20 && a <= 30){
		cout<<"Il numero inserito è compreso tra 20 e 30";
	}
	else{
		cout<<"Il numero inserito non è compreso tra 20 e 30";
	}
}

how to use and in c++

The ampersand symbol & is used in C++ as a
reference declarator in addition to being the address operator.
  The meanings are related but not identical. If you take the address 
  of a reference, it returns the address of its target. Using the previous 
  declarations, &rTarg is the same memory address as &target .