Given the current day of the week (1-7) add n days and indicate what day of the week (1-7) it will be then code example
Example: get day from date algo
dow(m,d,y){y-=m<3;return(y+y/4-y/100+y/400+"-bed=pen+mad."[m]+d)%7;}dow(m,d,y){y-=m<3;return(y+y/4-y/100+y/400+"-bed=pen+mad."[m]+d)%7;}