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C++ Exercises: Find the perfect numbers between 1 and 500

C++ For Loop: Exercise-4 with Solution

Write a program in C++ to find the perfect numbers between 1 and 500.

Pictorial Presentation:

C++ Exercises: Find the perfect numbers between 1 and 500

Sample Solution :-

C++ Code :

#include <iostream>
using namespace std;
int main() 
{
  cout << "\n\n Find the perfect numbers between 1 and 500:\n";
  cout << "------------------------------------------------\n";
  int i = 1, u = 1, sum = 0;
  cout << "\n The perfect numbers between 1 to 500 are: \n";
  while (i <= 500) 
  {
    while (u <= 500) 
    {
      if (u < i) 
      {
        if (i % u == 0)
          sum = sum + u;
      }
      u++;
    }
    if (sum == i) {
      cout << i << "  " << "\n";
    }
    i++;
    u = 1;
    sum = 0;
  }
}

Sample Output:

 Find the perfect numbers between 1 and 500:                           
------------------------------------------------                       
                                                                       
 The perfect numbers between 1 to 500 are:                             
6                                                                      
28                                                                     
496 

Flowchart:

Flowchart: Find the perfect numbers between 1 and 500

C++ Code Editor:

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C++ Programming: Tips of the Day

What is a smart pointer and when should I use one?

This answer is rather old, and so describes what was 'good' at the time, which was smart pointers provided by the Boost library. Since C++11, the standard library has provided sufficient smart pointers types, and so you should favour the use of std::unique_ptr, std::shared_ptr and std::weak_ptr.

There was also std::auto_ptr. It was very much like a scoped pointer, except that it also had the "special" dangerous ability to be copied - which also unexpectedly transfers ownership.

It was deprecated in C++11 and removed in C++17, so you shouldn't use it.

std::auto_ptr<MyObject> p1 (new MyObject());
std::auto_ptr<MyObject> p2 = p1; // Copy and transfer ownership. 
                                 // p1 gets set to empty!
p2->DoSomething(); // Works.
p1->DoSomething(); // Oh oh. Hopefully raises some NULL pointer exception.

Ref : https://bit.ly/3mc9GHE