Java Reference
In-Depth Information
Write a program that takes a value
x
as input and outputs this sum for
n
taken to
be each of the values 1 to 10, 50, and 100. Your program should repeat the
calculation for new values of
x
until the user says she or he is through. The
expression
n
! is called the
factorial
of
n
and is defined as
n
!
=
1 * 2 * 3 * . . . *
n
Use variables of type
double
to store the factorials (or arrange your calculation to
avoid any direct calculation of factorials); otherwise, you are likely to produce
integer overflow, that is, integers larger than Java allows.
8.
In cryptarithmetic puzzles, mathematical equations are written using letters.
Each letter can be a digit from 0 to 9, but no two letters can be the same. Here
is a sample problem:
SEND + MORE = MONEY
A solution to the puzzle is S = 9, R = 8, O = 0, M = 1, Y = 2, E = 5, N = 6, D = 7
Write a program that finds a solution to the cryptarithmetic puzzle of:
TOO + TOO + TOO + TOO = GOOD
The simplest technique is to use a nested loop for each unique letter (in this case
T, O, G, D). The loops would systematically assign the digits from 0 to 9 to each
letter. For example, it might first try T = 0, O = 0, G = 0, D = 0, then T = 0,
O = 0, G =0, D = 1, then T = 0, O = 0, G = 0, D = 2, etc., up to T = 9, O = 9,
G = 9, D = 9. In the loop body, test that each variable is unique and that the
equation is satisfied. Output the values for the letters that satisfy the equation.
