Read input numbers separated by spaces

Raymond Aaron picture Raymond Aaron · Oct 27, 2012 · Viewed 122.8k times · Source

This may be a total beginner's question, but I have yet to find an answer that works for me.

Currently, I'm writing a program for a class that takes in a user's input (which can be one or more numbers separated by spaces), then determines whether the number is prime, perfect, or neither. If the number is perfect, then it will display the divisors.

Thus far, I've already written the code for the prime, perfect, and listing the divisors. I'm stuck on the input portion of my program. I don't know how to get the input that's separated by spaces to go through my loops one at a time.

This is my current program:

cout<<"Enter a number, or numbers separated by a space, between 1 and 1000."<<endl;
cin>>num;

while (divisor<=num)
    if(num%divisor==0)
    {
        cout<<divisor<<endl;
        total=total+divisor;
        divisor++;
    }
    else divisor++;
if(total==num*2)
    cout<<"The number you entered is perfect!"<<endl;
else cout<<"The number you entered is not perfect!"<<endl;


if(num==2||num==3||num==5||num==7)
    cout<<"The number you entered is prime!"<<endl;

else if(num%2==0||num%3==0||num%5==0||num%7==0)
    cout<<"The number you entered is not prime!"<<endl;
else cout<<"The number you entered is prime!"<<endl;

return 0;

It works, but only for a single number. If anyone could help me to get it to be able to read multiple inputs separated by spaces, it'd be greatly appreciated. Also, just a side note, I do not know how many numbers will be entered, so I can't just make a variable for each one. It will be a random amount of numbers.

Thanks!

Answer

Murilo Vasconcelos picture Murilo Vasconcelos · Oct 27, 2012

By default, cin reads from the input discarding any spaces. So, all you have to do is to use a do while loop to read the input more than one time:

do {
   cout<<"Enter a number, or numbers separated by a space, between 1 and 1000."<<endl;
   cin >> num;

   // reset your variables

   // your function stuff (calculations)
}
while (true); // or some condition