#1 numere prime

#include<iostream>
using namespace std;
int main()
{
int n,c=0;
cout<<"Introdu n"; cin>>n;
for (int i=1; i<=n; i++)
{
if (n%i==0)
c++;
}
if (c==2)
cout<<"Numarul este prim";
else
cout<<"Numarul NU este prim";
return 0;
}

#2 lista numere prime

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

using namespace std;

int main()
{
    int i,x,d,OK;
    cin >> x;
    if (x>1)
    {
        cout << 2 << ' ';
        for (i = 3 ; i<=x ; i = i+2)
        {
            OK = 1;
            for (d = 3 ; d <= sqrt(i) and OK == 1; d = d+2)
                if (i % d == 0)
                    OK = 0;
            if (OK==1)
                cout << i << ' ';
        }
    }
    return 0;
}

#3 primele n numere prime

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

using namespace std;

int main()
{
    int i,x,d,OK;
    cin >> x;
    if (x>1)
    {
        cout << 2 << ' ';
        for (i = 3 ; i<=x ; i = i+2)
        {
            OK = 1;
            for (d = 3 ; d <= sqrt(i) and OK == 1; d = d+2)
                if (i % d == 0)
                    OK = 0;
            if (OK==1)
                cout << i << ' ';
        }
    }
    return 0;
}

#4 afisarea unui numar cu o subdiviziune

#include<iostream>
#include<math.h>
using namespace std;
int main()
{
    int n, k;
    int copien;
    cout<<"n=";
    cin>>n;
    if(n<0){n=n*(-1);}
    copien=n-1;
    cout<<"numarul cel mai mare mai mic decat "<<n<<" este = "<<copien;

    return 0;
}

#5 desc.
#include<iostream>
using namespace std;


int x;
int cifre;

int main()
{
    cout<<"x=";cin>>x;
    while(x>10){
    x=x/10;
    x++;}
    cout<<"x=" <<x;
}