Can't loop 1 step when transferring data?

Question

Multithreading

Each process is given an integer. Using the MPI_Send and MPI_Recv functions, perform a cyclic data shift with step 1 for all processes, sending the number from process 0 to process 1, from process 1 to process 2, ..., from the last process to process 0. In each process, output the resulting number.

#include <windows.h>
#pragma hdrstop
#include "mpi.h"
#include "pt4.h"
void Solve()
{
  Task("MPIBegin18");
  int flag;
  MPI_Initialized(&flag);
  if (flag == 0)
    return;
  int rank, size;
  MPI_Comm_size(MPI_COMM_WORLD, &size);
  MPI_Comm_rank(MPI_COMM_WORLD, &rank);
  MPI_Status s;
  int n;

  pt >> n;
  //Show(n);

  for (int i = 0; i < size; ++i)
  {

    MPI_Send(&n, 1, MPI_INT, i, 0, MPI_COMM_WORLD);
  }

  
}

that's what it is, whether it would have done an array without problems, but here something has no ideas. Help if not difficult