Gravity Simulator Problem

[noey699]

I cannot figure out what is going on when I run this gravity simulator. I put in the correct numbers for the variables but when I run it it doesn't do what I want to. In the while loops in int main it is supposed display the positions of object 1 and 2 update the positions as many times as the accuracy calls for then repeat it but it only updates the positions once. The next ones are all the same. I am using Dev-C++ on windows vista.

this is the code

#include <iostream>
#include "required.h"
#include <math.h>

//declare needed variables
using namespace std;
double force1;
int time3;
double x1, yone, z1;
double x2, y2, z2;
double Mass1;
double Mass2;
double velocityx1;
double velocityy1;
double velocityz1;
double velocityx2;
double velocityy2;
double velocityz2;
double accuracy;
int range;
int second = 0;
//F = GMm/R&#178;
//calculates gravity with the given parameters
double GravityCalc(double Mass1, double Mass2, double Distance){
    //declare variables for order
    double top;
    double botom;
    //G is 1.0 x10^10 times bigger
    double G = .667;
    double Force;
    
    //calculate gravity
    top = G * Mass1 * Mass2;
    botom = Distance * Distance;
    Force = top / botom;
    return Force;
}

//finds the distance in 3 dimensional space between two objects
double finddistance( double x1, double yone, double z1, double x2, double y2, double z2 ){
              //declare order variables
              double cx, cy, cz;
              double distance;
              //calculate the distances
              cx = x1 - x2;
              cy = yone - y2;
              cz = z1 - z2;
              distance = pow(cx, 2) + pow(cy, 2) + pow(cz, 2);
              distance = sqrt(distance);
              
              //return distance always positive
              if (distance > 0){
                           return distance;
              }
              if (distance < 0){
                           distance = distance * -1;
                           return distance;
              }
              
}

                      

int main(int argc, char *argv[]){
    double b = 0;
    double c = 0;
    //receive values of variables
    cout << "Enter mass of object 1: ";
    cin >> Mass1;
    cout << endl << "Enter mass of object 2: ";
    cin >> Mass2;
    cout << endl << "Enter position of object 1 x, y, and z:" << endl;
    cout << "x: ";
    cin >> x1;
    cout << endl << "y: ";
    cin >> yone;
    cout << endl << "z: ";
    cin >> z1;
    cout << endl << "Enter position of object 2 x, y, and z:" << endl;
    cout << "x: ";
    cin >> x2;
    cout << endl << "y: ";
    cin >> y2;
    cout << endl << "z: ";
    cin >> z2;
    cout << endl << "Enter the starting velocities of object 1:" << endl;
    cout << "x: ";
    cin >> velocityx1;
    cout << endl << "y: ";
    cin >> velocityy1;
    cout << endl << "z: ";
    cin >> velocityz1;
    cout << endl << "Enter the starting velocities of object 2:" << endl;
    cout << "x: ";
    cin >> velocityx2;
    cout << endl << "y: ";
    cin >> velocityy2;
    cout << endl << "z: ";
    cin >> velocityz2;
    cout << endl << "Enter the accuracy of the simulation from int between 0 and 1: ";
    cin >> accuracy;
    cout << endl << "Enter how long you want the sim to run in seconds: ";
    cin >> range;
    system("pause");
    system("cls");
    
    
    //update the positions according the range of the simulation and the accuracy
    while ( b <= range ){
          //display the positions
          cout << "Object 1 position: " << endl;
          cout << "x = " << x1 << "   y = " << yone << "   z = " << z1 << endl;
          cout << " Object 2 position: " << endl;
          cout << "x = " << x2 << "   y = " << y2 << "   z = " << z2 << endl << endl << endl;
          //calculate to the given accuracy
          while ( c <= 1 / accuracy ){
                //positionupdate function coded in required.h
                //calculate the force of the gravity between the two objects
                force1 = GravityCalc( Mass1, Mass2, finddistance(x1, yone, z1, x2, y2, z2) );
                //update positions of x
                x1 = x1 + positionupdate(accuracy, force1, vectorx( x1, yone, z1, x2, y2, z2, 1));
                x2 = x2 + positionupdate(accuracy, force1, vectorx( x1, yone, z1, x2, y2, z2, 2));
                //update positions of y
                yone = yone + positionupdate(accuracy, force1, vectory( x1, yone, z1, x2, y2, z2, 1));
                y2 = y2 + positionupdate(accuracy, force1, vectory( x1, yone, z1, x2, y2, z2, 2));
                //update positons of z
                z1 = z1 + positionupdate(accuracy, force1, vectorz( x1, yone, z1, x2, y2, z2, 1));
                z2 = z2 + positionupdate(accuracy, force1, vectorz( x1, yone, z1, x2, y2, z2, 2));
                
                //move loop forward
                c = c + 1;
          }
          //move loop forwards
          b = b + 1;
          
    }
    
    
    system("pause");
    return EXIT_SUCCESS;
}

[olivthill2]

Maybe the c variable needs to be initialized between the first and the second while line.

[g.eckert]

why are these global???

double force1;
int time3;
double x1, yone, z1;
double x2, y2, z2;
double Mass1;
double Mass2;
double velocityx1;
double velocityy1;
double velocityz1;
double velocityx2;
double velocityy2;
double velocityz2;
double accuracy;
int range;
int second = 0;

[treuss]

DESCRIPTION
`sqrt' computes the positive square root of the argument. You can modify error handling for this
function with `matherr'.

This should help you remove superfluous code