Answer to Question #236109 in C++ for SOM

Question

Give the syntax for pass by reference? Compare pass by reference and pass by pointer(address), and conclude which one is preferable and why?

Answer 1

Pass by reference syntax

datatype swap(datatype & x, datatype & y)

Example of pass by reference
#include <iostream>
using namespace std;
void swapNumbers(int& number1, int& number2)
{
    int z = number1;
    number1 = number2;
    number2 = z;
}
 
int main()
{
    int x = 65, y = 90;
    cout << "Before Swap\n";
    cout << "x = " << x << " y = " << y << "\n";
 
    swapNumbers(x, y);
 
    cout << "After Swap with pass by reference\n";
    cout << "x= " << x << " y = " << y << "\n";
}


 

Differences between pass by reference and pass by pointer

A reference cannot be reassigned once assigned while a pointer can be reassigned

A pass by pointer use * to dereference a pointer while pass by reference

does not require dereferencing and references can be used directly

Pass by reference is preferred over pass by pointer since references cannot be null, thus they are safe.