w3resource

C++ Exercises: Display the pattern power of 2, triangle

C++ For Loop: Exercise-54 with Solution

Write a program in C++ to display the pattern power of 2, triangle.

Sample Solution:-

C++ Code :

#include <iostream>
#include <math.h>
using namespace std;

int main()
{
    int i, j, spc, n, mm, d = 1, k;
    cout << "\n\n Display the pattern like pyramid with power of 2:\n";
    cout << "------------------------------------------------------\n";
    cout << " Input the number of rows: ";
    cin >> n;
    //----------- space for first line ----------------------
    for (i = 1; i <= n * 2 + 2 + 5; i++) //extra 5 spaces is the margin from left
        cout << " ";
    cout << pow(2, 0) << endl;
    for (i = 1; i < n; i++) 
    {
        //----------- printing spaces from 2nd line to end -------
        for (k = 1; k <= n * 2 - d + 5; k++) 
        {
            cout << " ";
        }
        //----------- print upto middle ----------------
        for (j = 0; j < i; j++) 
        {
            mm = pow(2, j);
            cout << mm << "  "; //print 2 spaces
        }
        //------------- print after middle to end -------
        for (j = i; j >= 0; j--) 
        {
            mm = pow(2, j);
            cout << mm << "  "; //print 2 spaces
        }
        d = d + 3;
        cout << endl;
    }
}

Sample Output:

Display the pattern like pyramid with power of 2:
------------------------------------------------------
 Input the number of rows:
                 1
              1  2  1  
           1  2  4  2  1  
        1  2  4  8  4  2  1  
     1  2  4  8  16  8  4  2  1  

Flowchart:

Flowchart: Display the pattern power of 2, triangle.

C++ Code Editor:

Contribute your code and comments through Disqus.

Previous: Write a program in C++ to display the pattern like right angle triangle with right justified using digits.
Next: Write a program in C++ to display such a pattern for n number of rows using number. Each row will contain odd numbers of number. The first and last number of each row will be 1 and middle column will be the row number. n numbers of columns will appear in 1st row.

What is the difficulty level of this exercise?



Share this Tutorial / Exercise on : Facebook and Twitter

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