Art of Code 01

Today, i write a simple program that prints squares in numbers, to prove that the sum of odd numbers are square.

If we have one item and add a odd number of items to it, the items forms a square.

• 2 Square = 4 = 1 + 3
• 4 Square = 16 = 1+3+5+7
• n Square = 1 + odd numbers

The Output of aoc_01-sumofofodd.cpp

1
4
9
16
25
36
49
64
81

A geometrical Prove of the sum of Odd is square:

appendix std::vector, auto and const

std::vector - Vectors

    vector<int> v = {1, 4, 2};

auto, explicit declared is so nineties ;-)

In “modern” c++, the compiler can decide which type applies.

    auto v = {1, 4, 2};
    for (auto i: v)
      cout << i << "\n";

We may also explicit tell the compiler we read only with const:

    auto v = {1, 4, 2};
    for (const int &i: v)
      cout << i << "\n";

aoc_01-sumofofodd.cpp

To compile and play with the sum of odds in C++:
g++ aoc_01-sumofofodd.cpp && ./a.out
or
clang++ -std=c++11 -stdlib=libc++ -g aoc_01-sumofofodd.cpp && ./a.out