Nested Structures. Error message: undefined reference to WinMain@16

[Saptaparnee_12]

#include <iostream>
#include <cmath>

using namespace std;

struct vectors
{
    double x,y,z;
};

struct ivector
{
    int ix,iy,iz;
};

struct vmodel
{
    int nx,ny,nz;                                         
    int nr;                                              

    struct vectors r1,r2;                                
    float dx,dy,dz;


    float *s1;                         
    float *rf;                         
    float *jp;                     
    int *ir;                              
    int *ij;                             
    int *layer;


};

I have this general C++ question. Do my nested structures look correct?

[dpiparo]

This post is a dupe. The original one has been answered.