#include <iostream>


// Solved: P1. Declare an integer with name (v) and initialize it with 2, in the global scope.
int v = 2;

// P2. Declare  an integer with name (u) and initialize it with v + 5, in the global scope.
int u=v+5;


// Solved: P3. Given the function declaration (header), return the square of a given double (x).
double square( double x )
{
    return x * x;
}

// P4. Given the function declaration (header), return the cube of a given double (x).
double cube( double x )
{
    return x * x * x;
}

// P5. Using for or while loop, compute the summation of integers from 1 to 15.
// Hints: before entering the loop, you need to declare and initialize a variable to accumulate the values.
int sumOfFirst15Integers (int sum)
{
   sum=0; int i=0;
   while(i<=15)
   {
       sum+=i;
       i++;
   }
   return sum;
}

// P6. Using while loop, compute the summation of first 15 odd integers (starting from 1).
// Hints: before entering the loop, make a 3 variables:
// 1- Counter for iteration over integers starting from 1,
// 2- Accumulater for summing odd integers,
// 3- And a variable that counts the odd integers, so the loop terminates once it reaches 15.

// Hints: use the expression ( x % 2 ) == 1 in if conditions to determine whether (x) is odd or even.
int sumOfFirst15OddIntegers(int sum)
{
    sum=0; int i=0; int j=0;
        while(j<15)
        {
            if(i%2==0)
            {
                i++;
            }
            else
            {
                sum+=i;
                i++;
                j++;
            }

        }
    return sum;
}

// You know that our DNA is double stranded. Each base has its complementary base.
// Adenine (A) binds to Thymine (T)
// Guanine (G) binds to Cytocine (C)
// Example:
// A-G-T-A-T-C-A-A-C
// T-C-A-T-A-G-T-T-G

// If you don't know what DNA is? see this short video: https://www.youtube.com/watch?v=zwibgNGe4aY

// P7. Given the following implemented function with (if-else if-else) that returns the complementary base,
// Convert this function to do the same logic with (switch-case).

namespace dna
{
 char complementaryBase( char base )
 {
    switch (base)
    {
    case 'A' :
        {
        return 'T';
        break;
        }
    case 'C':
    {
        return 'G';
        break;
    }
    case 'G':
    {
        return 'C';
        break;
    }
    case 'T':
    {
        return 'A';
        break;
    }
    }
 }
}
// P8. In the previous problem, enclose the function complementaryBase inside a namespace with name (dna).

int main()
{

    std::cout << "u = " << u << std::endl;
    std::cout << "The square of u = " << square( u ) << std::endl;
    std::cout << "The cube of u = " << cube( u ) << std::endl;

    std::cout << "The sum of integers from 1 to 15 = " << sumOfFirst15Integers() << std::endl;
    std::cout << "The sum of first 15 odd integers = " << sumOfFirst15OddIntegers() << std::endl;

    std::cout << "The complementary base of 'A' = "
              << dna::complementaryBase( 'A' ) << std::endl;

    std::cout << "The complementary base of 'C' = "
              << dna::complementaryBase( 'C' ) << std::endl;

    std::cout << "The complementary base of 'G' = "
              << dna::complementaryBase( 'G' ) << std::endl;

    std::cout << "The complementary base of 'T' = "
              << dna::complementaryBase( 'T' ) << std::endl;

    return 0;
}