#include using namespace std;void square1(int);// a function that pass variables by valuevoid square2(int&);// a function that pass variables by referencevoid square3(int*);// a function that pass variables by pointerint main(){ //Call-by-Value int n1 = 2; cout << "The value of n1 before the fucntion call is: " << n1 << endl; square1(n1); //call square1() to compute the square of n1 cout << "The value of n1 after the function call is: " << n1 << endl<