Xox

Trasnformare numar in baza 2
: int main()
{
    int n,nr=0,p=1;
    cin>>n;
    do{
        int c=n%2;
        n/=2;
        nr=nr+c*p;
        p*=10;
    }while(n);
    cout<<nr;
    return 0;
}

transformare nr din baza 2 in baza 10
 int main()
{
    int n,nr=0,p=1;
    cin>>n;
    do{
        int c=n%2;
        n/=10;
        nr=nr+c*p;
        p*=2;
    }while(n);
    cout<<nr;
    return 0;
}
transformare nr din baza 10 in baza 2
 int main()
{
    int n,nr=0,p=1;
    cin>>n;
    do{
        int c=n%2;
        n/=2;
        nr=nr+c*p;
        p*=10;
    }while(n);
    cout<<nr;
    return 0;
}
   suma prefixelor
while (x)
{
    s+=x:
    x/=10;
}

cmmdc(int a, int b)
{while(b>0)
{int r=a%b;
a=b;
b=r;}
cout<<a;}

cmmmc(a,b)=a*b/cmmdc(a,b);

suma divizorilor:

 for(int d=2;d<=n/2;d++)
 if(n%d==0)
         s+=d;
algoritm prime

int prime(int x)
{if(x<2||(x>2&&x%2==0))
  return 0;
for(int d=3;d*d<n;d+=2)
   if(n%d==0)
   return 0;
return 1;
}