Week $4$ Lab

For this week's program, you'll ask the user to enter a date, then using a bunch of if else statements, you'll determine what day of the week the date fell on$.$

For instance, if the user enters the date $3/14/2015,$ your program will determine that was a Saturday. You'll probably want to ask for the month, day, and year with three separate inputs.

Not a lot of problem solving this week, just lots of if else statements to work through. The following describes how to calculate the day of the week based on the date. $3/14/2015$ will be used throughout the explanation.

Start with the last two digits of the year, in this case $15,$ divide by $4$ and get rid of the remainder, $\frac{15}{4}=>3,$ then add this number back onto the last two digits of the year, $15+3=18.$ We'll come back for this $18$ later.

The next number we need is based on the month entered. We'll use

$0$ if the month is April or July

$1$ if the month is January or October

$2$ if the month is May

$3$ if the month is August

$4$ if the month is February, March, or November

$5$ if the month is June

$6$ if the month is September or December

For March we'll use $4.$

The next number we need will be based on the century

$0$ for the $1500$ s or $1900$ s

$2$ for the $1800$ s or $2200$ s

$4$ for the $1700$ s or $2100$ s

$6$ for the $1600$ s or $2000$ s

For $2015,$ we'll use $6.$

You will need to subtract one if you have a date in January or February of a leap year. We won't subtract anything since $2015$ wasn't a leap year.

Now that we've done all that, we going to add the numbers we got from the Year, Month, Century, and the actual date, $14$ in this case, then we'll subtract one for January or February of a leap year. $18+4+6+14=42.$ Next we'll mod the result by $7$ to find the day of the week, where $0$ represents Saturday and $6$ represents Friday. $42$ mod $7$ is $0,$ so $3/14/2015$ was a Saturday. So that it looks nice, your final output should be something like $3/14/2015$ was a Saturday.

In case you didn't know, a leap year occurs in a year that is evenly divisible by $4,$ unless the year is also evenly divisible by $100,$ then it's not a leap year, unless the year is also evenly divisible by $400,$ then it's back to a leap year.

Using C$++$