C++/Function/Function Return

Returning a Value from a Function

<source lang="cpp">

1. include <iostream>

using namespace std; int addNumbers(int, int); int main () {

  int firstNum, secondNum, sum = 0;
  cout << "Enter first number: ";
  cin >> firstNum;
  cout << "Enter second number: ";
  cin >> secondNum;
  sum = addNumbers (firstNum, secondNum);
  cout << firstNum << " + " << secondNum << " = " << sum;
  return 0;

} int addNumbers (int x, int y) {

  return x + y;

}

      </source>

Returning objects.

<source lang="cpp">

1. include <iostream>

using namespace std;

class MyClass {

 int val; 

public:

 MyClass(int i) { 
   val = i; 
   cout << "Inside constructor\n"; 
 } 

 ~MyClass() { 
    cout << "Destructing\n"; 
 } 

 int getval() { 
    return val; 
 } 
 
 MyClass mkBigger() { 
   MyClass o(val * 2); 

   return o;              // Return an object. 
 } 

};

void display(MyClass ob) {

 cout << ob.getval() << "\n"; 

}

int main() {

 cout << "Before constructing a.\n"; 
 MyClass a(10); 
 cout << "After constructing a.\n"; 

 cout << "Before call to display().\n"; 
 display(a); 
 cout << "After display() returns.\n"; 

 cout << "Before call to mkBigger().\n"; 
 a = a.mkBigger(); 
 cout << "After mkBigger() returns.\n"; 

 cout << "Before second call to display().\n"; 
 display(a); 
 cout << "After display() returns.\n"; 

 return 0; 

}

      </source>

Return Value Of Functions

<source lang="cpp">

1. include <iostream>
2. include <iomanip>

using namespace std; double area(double, double); int main() {

   double  x = 3.5, y = 1.2,  res;
   res = area( x, y+1);
   cout << fixed << setprecision(2);
   cout << " The area of a rectangle "
        << " with width  " << setw(5)  << x
        << " and length  " << setw(5) << y+1
        << " is          " << setw(5) << res
        << endl;
   return 0;

} double area( double width, double len) {

   return (width * len); 

}

      </source>