Thread: New Programming Student Looking for Help

Hello everyone I am new to this site I have recently joined the university of Computer science in Greece and although we have never used java before our teacher in ''programming with java'' has given us some homework,that I believe, is really difficult for a beginner so I could really use your help.I am not looking for a clear out solution which I will copy paste.I am looking for someone to show me a program that could do what I want it to do and then explain me how it works and some parts that I possibly will not understand.So here is the problem.I want my program to take two dates which will be given by the user and calculate the days that have passed from the one date to the other.The first date will be today and the second one will be any date from the past.Also after it calculates the days passed it should also find what day was the past date.I need to state that I cant use anything that does the procedure automatically so it should be done with plain orders not even loops if possible just ''if'' .Thanks a lot for your help looking forward to some answers.If anything is unclear please ask me so I can clarify.Sorry if my english is bad,but I havent used them for a while.
Looking forward to your replies,
Nikos

So here is the program I have created in order to solve this.
import acm.program.*;
public class ask2 extends Program {
public void run() {
println ("Give the first date.Year,Month,Day");
int year1 = readInt();
int month1 = readInt();
int day1 = readInt();
println("Give the second date.Year,Month,Day");
int year2 = readInt();
int month2 = readInt();
int day2 = readInt();
int daydifference= 0;
boolean logic1;
for (int i=year2;i<year1;i++){
logic1=(i%400==0)||((i%4==0)&&(i%100!=0));
if (logic1) {
daydifference=daydifference + 366;
}
else{
daydifference=daydifference + 365;
}
}
boolean logic2;
boolean logic3;
boolean logic4;
for (int i=month2;i<month1;i++){
logic2=(i==1)||(i==3)||(i==5)||(i==7)||(i==8)||(i= =10)||(i==12);
logic3=(i==4)||(i==6)||(i==9)||(i==11);
logic4= ((i==2)&&((year1%400==0)||((year1%4==0)&&(year1%10 0!=0))));
if ((month1-month2)>0) {
if (logic2) {
daydifference=daydifference + 31;
}
else if (logic3){
daydifference=daydifference + 30;
}
else if (logic4){
daydifference=daydifference + 29;
}
else if (! logic4){
daydifference=daydifference + 28;
}
}
}
for (int i=month1;i<month2;i++){
logic2=(i==1)||(i==3)||(i==5)||(i==7)||(i==8)||(i= =10)||(i==12);
logic3=(i==4)||(i==6)||(i==9)||(i==11);
logic4= ((i==2)&&((year1%400==0)||((year1%4==0)&&(year1%10 0!=0))));
if ((month1-month2)<0) {
if (logic2) {
daydifference=daydifference - 31;
}
else if (logic3){
daydifference=daydifference - 30;
}
else if (logic4){
daydifference=daydifference - 29;
}
else if (! logic4){
daydifference=daydifference - 28;
}
}
}
if ((day1-day2)>0) {
daydifference=daydifference + (day1-day2);
}
else {
daydifference=daydifference - (day2-day1);
}
println("The days that have passed between those dates are " +daydifference);
}
}


My problem is that it gives me the day difference but with 1 day less.Could anyone see the problem here?Also I could really use some help on the part of finding what day it was that date

I have come ro realize that possibly this problem only occurs when of the given months is december.I think that if the months given are not december it works perfectly fine

do you have any reccomendations about the part of the leap year and the part of december and such?Also I didnt really get the day calculation thing

Originally Posted by NikosNt

do you have any reccomendations about the part of the leap year

No.

Originally Posted by NikosNt

Also I didnt really get the day calculation thing

Suppose we are given a reference date that falls on Monday. There are seven days in a week, right?

Then, if there are N days from that date until the target date, and if N is divisible by 7, it's Monday again, since there are an integer number of weeks from reference to target.

Suppose, for simplicity, there are 21 days between the reference date and the target date.

Since 21%7 == 0 that means it's Monday. (That is, there are an integer number of weeks. So the weekday is the same.)

Suppose there are 22 days.

Since 22 % 7 == 1, that means it's Tuesday (Since there is a remainder of 1 after dividing by 7, that means there is one more day than an integer number of weeks.)

Supose there are 40123 days.

Since 40123 % 7 == 6, that means it's Sunday (Since there is a remainder of 6 after dividing by 7, that means there are six more days than an integer number of weeks.)


Cheers!

Z

what If I dont have a given date? I mean if I dont know what day it is for any day

I already told you one that you can use: Jan 1, 1900 is Monday. If you would rather have some other date, then look it up on one of the many calendar programs that you can find on the web.

Cheers!

Z

I cannot use any date I want there are some restrictions.I actually cant use any date

So, what date can you use for a reference? I mean you have to start somewhere.

What, exactly, are these restrictions?

Cheers!

Z

we can ask the user to say what name is the first date of the present but he said it's not necessary and had to allow us to do it since lots of people asked for it

the earlierst date is the first day of the first year so propably 1/1/1

thanks a lot for your effort to help me (even though I didnt like a part of the last message).
Cheers
Nikos