Need some help for my program

[buomque]

I'm writing a program that determine if that is prime or perfect numbers and output factors of them. If 6 is the first input, the output will say it's a perfect number but if i input 6 again it says 6 is not a prime. Could use some help here. Thanks!

#include <iostream> 
using namespace std;
int main ()
{
    int num, range=1000;
    int n;
    int divisor;
    int sum=0;
 
   const int SENTINEL=-1;    
    cout<<"enter integers between 1 and 1000 <enter -1 to exit> :";
    cin>>num;                          
      if(0<num && num<=range)
    {           
 
    while(num!=SENTINEL)    
    {         
        for ( n=2; n < num; n++ ) 
            if (num%n==0 )        
 
                break;                             
            if ( n==num )      
                cout << num<<" is prime"<< endl;
            else 
            {   
                cout << num << " is not prime" <<endl;
                for(divisor=1; divisor <= num/2; divisor++)                    
                    if (( num%divisor==0) && (num!=divisor))
                    {
                        cout << "The factor of " << num << " is: " << divisor << endl;
                       sum +=divisor ; 
 
                         if(sum==num)
                         cout << num << " is a perfect number" << endl;                        
                    }                
            }          
            cin>>num;          
    }     
    }
 
    else
    cout<<"invalid Number, number should be between 1 and 1000";      
    return 0;
}

[amitpatel66]

I'm writing a program that determine if that is prime or perfect numbers and output factors of them. If 6 is the first input, the output will say it's a perfect number but if i input 6 again it says 6 is not a prime. Could use some help here. Thanks!

#include <iostream>
using namespace std;
int main ()
{
int num, range=1000;
int n;
int divisor;
int sum=0;

const int SENTINEL=-1;
cout<<"enter integers between 1 and 1000 <enter -1 to exit> :";
cin>>num;
if(0<num && num<=range)
{

while(num!=SENT INEL)
{
for ( n=2; n < num; n++ )
if (num%n==0 )

break;
if ( n==num )
cout << num<<" is prime"<< endl;
else
{
cout << num << " is not prime" <<endl;
for(divisor=1; divisor <= num/2; divisor++)
if (( num%divisor==0) && (num!=divisor))
{
cout << "The factor of " << num << " is: " << divisor << endl;
sum +=divisor ;

if(sum==num)
cout << num << " is a perfect number" << endl;
}
}
cin>>num;
}
}

else
cout<<"invalid Number, number should be between 1 and 1000";
return 0;
}

Why is yur code with lots of for and if conditions just to find if it is prime or not??
a single for loop with running through num/2 and checking num%n ==0 will help you find out the prime or not.
Have a flag = 0, set flag = 1 if num%n =0 then finally check if flag = 0 then number is prime else not prime....