A C++ program can be made easier to read and maintain by using references rather than pointers. A C++ function can return a reference in a similar way as it returns a pointer.

When a function returns a reference, it returns an implicit pointer to its return value. This way, a function can be used on the left side of an assignment statement. For example, consider this simple program:

#include 
     
      #include 
      
        using namespace std; double vals[] = {
   10.1, 12.6, 33.1, 24.1, 50.0}; double& setValues( int i ){  return vals[i];   // return a reference to the ith element} // main function to call above defined function.int main (){    cout << "Value before change" << endl;   for ( int i = 0; i < 5; i++ )   {       cout << "vals[" << i << "] = ";       cout << vals[i] << endl;   }    setValues(1) = 20.23; // change 2nd element   setValues(3) = 70.8;  // change 4th element    cout << "Value after change" << endl;   for ( int i = 0; i < 5; i++ )   {       cout << "vals[" << i << "] = ";       cout << vals[i] << endl;   }   return 0;}
      
     

 

When the above code is compiled together and executed, it produces the following result:

Value before changevals[0] = 10.1vals[1] = 12.6vals[2] = 33.1vals[3] = 24.1vals[4] = 50Value after changevals[0] = 10.1vals[1] = 20.23vals[2] = 33.1vals[3] = 70.8vals[4] = 50

 

When returning a reference, be careful that the object being referred to does not go out of scope. So it is not legal to return a reference to local var. But you can always return a reference on a static variable.

int& func() {   int q;   //! return q; // Compile time error   static int x;   return x;     // Safe, x lives outside this scope}