Don't include a comma after the last item in a printed list

Question

I have a list of numbers that are printed:

1: 1,
2: 1, 2,
3: 1, 3,

How do I not include that last comma on each line?

for ( int i = 1; i <= x; ++i )
  {
    cout << i << ": ";
    for ( int j = 1; j <= i; ++j )
    {
      if ( i % j == 0 )
      {
        cout << j << ", ";
      }
    }
    cout << endl;
  }

Please share with us your code... – Ionică Bizău Oct 17 '13 at 03:42 — Ionică Bizău, Oct 17 '13 at 03:42
how are you producing these numbers? – codedude Oct 17 '13 at 03:43 — codedude, Oct 17 '13 at 03:43
Cut it off with some scissors? Please post some code. – Oct 17 '13 at 03:43 — , Oct 17 '13 at 03:43
I recommend using the backspace key. – codedude Oct 17 '13 at 03:45 — codedude, Oct 17 '13 at 03:45
Instead, print the comma before every item but the first. – Retired Ninja Oct 17 '13 at 03:52 — Retired Ninja, Oct 17 '13 at 03:52

score 2 · Accepted Answer · answered Oct 17 '13 at 03:54

2

Try this:

for ( int i = 1; i <= x; ++i )
{
cout << i << ": ";
for ( int j = 1; j <= i; ++j )
{
  if (i==j) {
      cout << j;      
   } else if ( i % j == 0 ) {
       cout << j << ", ";
  }
}
cout << endl;
}

answered Oct 17 '13 at 03:54

codedude

6,244
14
63
99

Necronomicron · Answer 2 · 2013-10-17T04:07:05.953

1

Try to check if number is the last, smth like:

for (int i = 1; i <= x; i++)
{
    cout << i << ": ";
    for (int j = 1; j <= i; j++)
        if (!(i % j))
        {
            if (j != i)
                cout << j << ", ";
            else
                cout << j << endl;
        }
}

edited Oct 17 '13 at 04:07

answered Oct 17 '13 at 03:52

Necronomicron

1,150
4
24
47

Code added. Can't use arrays. – calf Oct 17 '13 at 03:55
I've made a mistake, already correct it. – Necronomicron Oct 17 '13 at 04:00

score 0 · Answer 3 · answered Oct 17 '13 at 03:56

for ( int i = 1; i <= x; ++i )
{
    cout << i << ": ";
    for ( int j = 1; j <= i; ++j )
    {
        if ( i % j == 0 )
        {
            cout << j;
            if (i != j) {
                cout << ", ";
            }
        } 
    }
    cout << endl;
}

cup · Answer 4 · 2013-10-17T04:40:50.370

Since you always output 1, start checking at 2

for ( int i = 1; i <= x; ++i )
{
   cout << i << ": 1";
   for ( int j = 2; j <= i; ++j )
   {
        if ( i % j == 0 )
        {
             cout << ", " << j;
        }
   }
   cout << endl;
}

Alternatively, you could play with the separator

for ( int i = 1; i <= x; ++i )
{
   char sep = ':'
   cout << i;
   for ( int j = 1; j <= i; ++j )
   {
        if ( i % j == 0 )
        {
             cout << sep << " " << j;
             sep = ',';
        }
   }
   cout << endl;
}

Don't include a comma after the last item in a printed list

4 Answers4