Increment dates by months in X++

A question was asked in the forums, about how to increment dates by months like:
21/02/2015
21/03/2015
21/04/2015
etc.

nextMth and dateMthFwd was suggested, so I just wanted to list some options.

Consider these examples.

nextMth will be off by days after hitting uneven months:

static void TestNextMth(Args _args)
{
    date d = nextMth(31\12\2015);
    print d;
   
    d = nextMth(d);
    print d;
   
    d = nextMth(d);
    print d;
   
    d = nextMth(d);
    print d;

    pause;
}

• 31/1/2016
• 29/2/2016
• 29/3/2016
• 29/4/2016

dateMthFwd works ok:

static void TestDateMthFwd(Args _args)
{
    date d = mkDate(31, 12, 2015); 
    
    print dateMthFwd(d, 1);     
    print dateMthFwd(d, 2);
    print dateMthFwd(d, 3);
    print dateMthFwd(d, 4);    
    pause;
}

• 31/1/2016
• 29/2/2016
• 31/3/2016
• 30/4/2016

And System.DateTime.AddMonths works ok:

static void TestAddMonths(Args _args)
{
    System.DateTime dateTime = new System.DateTime(2015, 12, 31);
    
    print dateTime.AddMonths(1);
    print dateTime.AddMonths(2);    
    print dateTime.AddMonths(3);
    print dateTime.AddMonths(4);    
    pause;
}

• 31/1/2016
• 29/2/2016
• 31/3/2016
• 30/4/2016