﻿ C++ Exercises: Display the number in reverse order - w3resource # C++ Exercises: Display the number in reverse order

## C++ For Loop: Exercise-30 with Solution

Write a program in C++ to display the number in reverse order.

Pictorial Presentation: Sample Solution:-

C++ Code :

``````#include <iostream>
using namespace std;

int main()
{
int num, r, sum = 0, t;
cout << "\n\n Display the number in reverse order:\n";
cout << "-----------------------------------------\n";
cout << " Input a number: ";
cin >> num;
for (t = num; num != 0; num = num / 10)
{
r = num % 10;
sum = sum * 10 + r;
}
cout << " The number in reverse order is : " << sum << endl;
}
``````

Sample Output:

``` Display the number in reverse order:
-----------------------------------------
Input a number: 12345
The number in reverse order is : 54321
```

Flowchart: 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