Cannon

#include <iostream>
#include <cmath>
#include <string.h>
#include <limits.h>
#include <iomanip>

using namespace std;

const double gravity = 9.8;

int main()
{
    //Declaration
    {
    double angleDeg = 0.0, v = 0.0, angleRad = 0.0, R = 0.0, x = 0.0, y = 0.0, T = 0.0, t = 0.0, i;// v = velocity
    bool done = false;

    //input
    cout <<"What's the angle?" <<endl;
    cin >> angleDeg;

        while (angleDeg < 0 || angleDeg > 90){  // between 0 to 90
            cout << "Between 0~90 angle please :)" << endl;

        while(!(cin >> angleDeg)) // Loops that goes on until cin fails
        {

            cin.clear(); // if fails, clear the failed flag.
            while(cin.get() != '\n'){} // A loop the cleans out anything that is left over in the input stream.

            cout << "Only numbers please: " << endl << "What's the angle again?" <<endl;// Output failed prompt. And requires only numbers
        }



                                            }

    cout << "Velocity?" <<endl;
    cin >> v;
        while (v < 0){  // between 0 to 90
            cout << "You know you can't go negative.. :)" << endl;

        while(!(cin >> v)) // Loops that goes on until cin fails
        {

            cin.clear(); // Clears cin if fails
            while(cin.get() != '\n'){} // A loop the cleans out anything that is left over in the input.

            cout << "Only numbers please: " << endl << "What's the velocity again?" <<endl;// Output failed prompt. And requires only numbers

        }



                     }
    //processing
    angleRad = angleDeg*M_PI/180.0;
    R = (pow(v, 2.0)/gravity)*sin(2.0*angleRad); // = (v^2/g)sin(2x) Trajectory formula (googled the right formula..)
    T = (2.0*v*sin(angleRad))/gravity; // Total time
    x = (v*cos(angleRad)); // x coordinate
    y = (v*sin(angleRad)); // y coordinate

        {

    //output
    cout << "Your total distance: " << R << "meters" << endl << endl;
    cout << "Your travel time is: " << T << "s" << endl << endl;
    cout << "Max X coordinate: " << x << "meters" << endl << endl;
    cout << "Max Y coordinate: " << y << "meters" << endl << endl;

            }
    cout << "Distance" << endl;
    cout << "----------" << endl;

    double a = R/20;
    double b = x/20;                    //Declaring doubles
    double c = y/20;

    for (double i = R/20; i <= R; i = i + a)// Diving total distance by 20 and finding point
    {                                       // Which start with distance1/20 ~ distance20/20
        cout << i << endl;
    }

         cout << endl << "X-Coordinates";
         cout << endl << "--------------" << endl;


       for (double o = x/20; o <= x/2; o = o + b) // Incrementing the X Vector.
        {
            cout << o << endl;
        }
            for  (double o = x/2; o > x/21; o = o - b) // Decrementing the X Vector.
            {
               cout << o << endl;
            }


         cout << endl << "Y-Coordinates";
         cout << endl << "--------------" << endl;

                for (double p = y/20; p <= y/2; p = p + c) // Incrementing the Y Vector.
                {
                    cout << p << endl;
                }
                        for (double p = y/2; p > y/21; p = p - c)// Decrementing the Y vector.
                        {
                            cout << p << endl;
                        }

    cout<< endl << "Thank you for using the program!" << endl;

   return 0;
            }
        }