I don't want a comma after the last number/value, how do i remove it (c++, loop)

Question

So, my friend's program is supposed to find the Multiplicative of Number three then print them out with a comma between the number. And not for the last one.

int a;
int b;

cout<< "First Number = ";
cin>>a;
cout<< "Last Number = ";
cin>>b;

if(a<=b)
{
    for(a;a<=b;a++)
    {
        if(a%3 == 0 && a%2 != 0)
        {   
            cout<<a;
        }
        if(a<b && a%3==0 && a%2 != 0)
        {
            cout<< " , ";
        }
        else if(a==b)
        {
            cout<< ".";
        }
    }
}

And after i input

a = 1

b = 20

this is what i expected

3 , 9 , 15.

and this is what i actually get

3 , 9 , 15 , .

Possible duplicate of [Printing lists with commas C++](https://stackoverflow.com/questions/3496982/printing-lists-with-commas-c) — Barmar, Nov 04 '17 at 05:28
This answer may help https://stackoverflow.com/questions/36137997/convert-vectorunsigned-char-1-2-3-into-string-1-2-3-as-digits/36138229#36138229 — Galik, Nov 04 '17 at 05:39

Galik · Accepted Answer · 2017-11-04T05:50:25.543

1

I would do something like this:

char const* sep = ""; // item separator (nothing to begin with)

for(a;a<=b;a++)
{
    if(a%3 == 0 && a%2 != 0)
    {   
        cout << sep << a; // output the separator before the next value
        sep = ", "; // now change it to a comma
    }
}

cout << "."; // finish with a full stop

edited Nov 04 '17 at 05:50

answered Nov 04 '17 at 05:43

Galik

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it gives me "Error 'sep' does not name a type" and "Error 'sep' was not declared in this scope" – FcIp3 Nov 04 '17 at 05:49
@FcIp3 perhaps you are using an older version of the standard. I edited the code so it should hopefully work now. – Galik Nov 04 '17 at 05:51

I don't want a comma after the last number/value, how do i remove it (c++, loop)

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