Write a main program to do the following: 1) Open a file called route.txt and co

Question

Write a main program to do the following:

1) Open a file called route.txt and connect it to the stream fin using

2) Define an array called the_planets of 10 planet pointers

3) Each element of the array is to point to a particular planet, the details of which come from the file. Therefore use your generate_planet function within a loop to achieve this, maybe using the line.
the_planets [i]=generate_planet(fin);

4) Report the details of all the planets to the screen by using your report_planet function within a loop. Be careful that the_planets[i] is a pointer to a planet.

5) I want to scan through all possible routes and find the shortest one please

Some comments:

To find the shortest route we will just do an exhaustive search – just considering all possible routes in turn. So with 3 planets we could do

Our Base – the_planets[0] – the_planets[1] – the_planets[2] – our base

or

rOur Base – the_planets[0] – the_planets[2] – the_planets[1] – our base

or

Our Base – the_planets[2] – the_planets[0] – the_planets[1] – our base

etc

We’ll limit ourselves to small numbers of locations to keep the calculation practical (use the first 6 locations in route.txt) but please don’t assume a fixed number.

We need to generate all possible routes. If we have n delivery locations then we will specify a route by an integer array defined asint *route=new int[n];Each possible route will characterised as followsroute[0] – first delivery locationroute[1] – second delivery location etc

Therefore the planets would be visited in the orderthe_planets [route[0]] - the_planets [route[1]] - the_planets [route[2]] - etc

*********************************************************************************************************

From Example 5, there is a example program

My Program:

#include<iostream>

#include<fstream>

#include<cmath>
using namespace std;
class planet
{
public:
int id;

float x;

float y;

float z;
};
planet *generate_planet(ifstream &fin)
{
planet *p = new planet; fin >>p->id >>p->x >>p->y >>p->z; return p;
}
void report_planet(planet *p)
{
cout<<p->id<<" ";
cout<<p->x<<" ";
cout<<p->y<<" ";
cout<<p->z<<endl;
}double pdistance(planet &p1,planet &p2)
{
float x=p1.x-p2.x;
float y=p1.y-p2.y;
float z=p1.z-p2.z;
double distance=sqrt(pow(x,2)+pow(y,2)+pow(z,2));
return distance;
}
unsigned long int factorial(int n)
{
if( n == 1 || n == 0)
return 1;
else
return n * factorial(n-1);
}

int main(){ ifstream fin("route.txt");

planet* the_planets[6];
int Number_0f_Planets;
fin >> Number_0f_Planets;
for(int i = 0; i < Number_0f_Planets; i++)
the_planets[i]=generate_planet(fin);
cout<<"Planet Id ";cout<<"x-position ";cout<<"y-position ";cout<<"z-position"<<endl;
for(int i = 0; i < Number_0f_Planets; i++)
report_planet(the_planets[i]);
double total=0;
for(int i = 0; i < Number_0f_Planets; i++)
total = total + pdistance(*the_planets[i], *the_planets[i+1]);
total += pdistance(*the_planets[0], *the_planets[Number_0f_Planets-1]);
cout<<"The total distance is:"<<total<<endl;
int *route = new int(Number_0f_Planets);
unsigned long int k, fi = factorial(Number_0f_Planets);

for( k = 0; k < fi ; k++)
{
for(int j = 0; j < Number_0f_Planets; j++)

route[j] = j;
unsigned long int ft = 1;
for(int j = 2; j <= Number_0f_Planets; j++)
{
ft = ft * (j-1);
int s = j-(( k / ft) % j);
int tmp = route[s-1];
route[s-1] = route[j-1];
route[j-1] = tmp;
}
cout<<" The Possible Route: ";
for(int i=0;i<Number_0f_Planets;i++)
cout<<the_planets[route[i]]->id<< " -> ";
}
return 0;}

Thank you very much !

Explanation / Answer

Yes, there are some problems with your code. The problems are numerous and intertwined. It looks like an effort to "force" the program to work has been made. For starters: 1 2 3 4 #include #include #include using namespace std;// put this here. No need for it to appear anywhere else. Next: You declare (but never use) an array of 10 planet pointers. I think it's these pointers which the function generate_planet() is meant to provide values for. It would work if generate_planet allocates an instance of planet, fills it with values from the file then returns a pointer to the planet. I think the program would work better if you used the following: 1 2 3 4 5 6 ifstream fin; fin.open ("route.txt");// add code to test for failure here before continuing with the file read fin >> temp_size; planet **the_planets = new planet*[temp_size];// creates an array of temp_size planet pointers for (i=0; i> new_planet->planet_id; fin >> new_planet->x; fin >> new_planet->y; fin >> new_planet->z; return new_planet; } Then: 1 2 for (i=0; i

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

---