Hi im trying to have my if statement equal to more then one number

I know this is incorrect and I cant figure it out. Do I just need to change my whole method? This website also said that this have question has been ask, but none of them help me at all.

public Date(int cMonth, int cDate, int cYear, int cDayToDate, String cStrMonth, int dayYear){
        if (cMonth = 01 && 12){
            month = cMonth;
            if (cMonth = 01,03,05,07,08,10,12){
            if (cDate <= 31 ){
            date = cDate;
            }// end of if
            }// end of if(cMonth) months with 31 days
        else if(cMonth = 04, 06, 09, 11){
            if (cDate <=30){
                date = cDate;
            }
}// end of cMonth month within 30 days