Ответ:

#include <iostream>
using namespace std;
int main()
{
    int a;
    cin >> a;
    cout <<"The next number for the"<< endl;
    cout << "number " << a << " is " << a+1 << "." << endl;
    cout << "The previous number for the" << endl;
    cout << "number " << a << " is " << a-1 << ".";
    return 0;
}