Cristian: Added another exercise

2010-11-15T12:43:51Z

Added another exercise

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= Introductory Exercises =

This is a small list of exercises for beginners. Some of them require minimal math knowledge. I will try and make references to that knowledge, when possible.

== Problems with numbers (no sequences as input) ==

=== First Degree Equation i ===
Solve the first degree equation with one variable: <code>ax + b = 0</code>, given <code>a</code> and <code>b</code> as input.
=== Second Degree Equation i ===
Solve the second degree equation with one variable: <code>ax2 + bx + c = 0</code>, given <code>a, b</code> and <code>c</code> as input.
=== Divisibility Test i ===
Find out if <code>n</code> is divisible by <code>k</code>.
=== Leap Year Test i ===
Find out if year <code>y</code> is a leap year.
=== kth digit ===
Extract the kth digit of a number, counting digits from right to left
=== Triangle Edges i ===
Can three input numbers be the lengths of the three edges of a triangle?
=== Swap Variables i ===
Given variables <code>a</code> and <code>b</code> exchange their values so that in the end <code>a</code> will contain the old value of <code>b</code> and <code>b</code> will contain the old value of <code>a</code>.
=== Swap Variables Restricted i h ===
Given variables <code>a</code> and <code>b</code> exchange their values so that in the end <code>a</code> will contain the old value of <code>b</code> and <code>b</code> will contain the old value of <code>a</code>, '''without''' using any other variables.

=== Divisors ===
Display all of number <code>n</code>'s divisors.
=== Primality ===
Is number <code>n</code> a prime number?
=== Reverse Digits ===
Display in reverse order the digits of a number <code>n</code>
=== Multiple Count i h ===
How many integers divisible by <code>n</code> lie in interval <code>[a, b]</code>?
=== Leap Year Count i h ===
How many years between <code>y1</code> and <code>y2</code> are leap years?
=== Palindrome h ===
Is number <code>n</code> a [[http://en.wikipedia.org/wiki/Palindrome palindrome]]? A palindrome is a symmetrical number, like 15351 or 12233221.
=== Sort numbers i===
Display three input integers in ascending order.
=== Sort more numbers i h===
Display five input integers in ascending order. Make the flow chart fit on one letter page.
=== GCD and LCM ===
Find the [[http://en.wikipedia.org/wiki/Gcd greates common divisor]] and the [[http://en.wikipedia.org/wiki/Lowest_common_multiple lowest common multiple]] of two numbers. Use [[http://en.wikipedia.org/wiki/Euclidean_algorithm Euclid's algorithm]]. Example: GCD of 24 and 32 is 8.
=== Prime Factors ===
Display the [[http://en.wikipedia.org/wiki/Prime_factors prime factor decomposition]] of input number <code>n</code>. Example: 1176 = 23 x 31 x 72
=== Numbers with two digits ===
Is number <code>n</code> formed with exactly 2 digits repeated any number of times? 23223 and 900990 are such numbers, while 593 and 44002 are not.
=== Decimal Fraction h===
Display fraction <code>m/n</code> in decimal format, with the period between brackets. Example: 13/30 = 0.4(3)
=== Number Guessing ===
Guess a number between 1 and 1024 by asking questions of the form "is the number greater or equal to x".

''Legend:''
* '''i''' means that the problem can be solved without loops, using only '''i'''f-then-else structures.
* '''h''' means '''h'''ard. The problem is difficult.

Introductory Exercises - Revision history

Cristian: Added another exercise