Coding Exercises: Loops and Algorithms
Implement the following functions, including unit tests. A few example tests are shown (commented). Add at least 3 more tests of your own for each function.
1. Sum of squares
Write a function sumOfSquares(int n) that calculates
and returns the sum \(1^2 + 2^2 + 3^2 ...
+ n^2\).
sumOfSquares(1) -> 1
sumOfSquares(2) -> 1+4 = 5
sumOfSquares(3) -> 1+4+9 = 142. Count occurrences
Write a function that counts the number of times one string occurs in another.
countOccurrences("Mississippi", "iss") -> 2
countOccurrences("banananana", "na") -> 43. Reverse
Write a function that returns the reverse of a string.
reverse("bad") -> "dab"
reverse("Hello, world!") -> "!dlrow ,olleH"
reverse("tacocat") -> "tacocat"4. Factorial
Implement the function factorial(int n) that
calculates the factorial \(n! = n \cdot
(n-1) \, \cdot \, ... \, \cdot \, 1\).
factorial(0) -> 1
factorial(1) -> 1
factorial(2) -> 2*1 = 2
factorial(3) -> 3*2*1 = 6
factorial(4) -> 4*3*2*1 = 24
factorial(5) -> 5*4*3*2*1 = 1205. Interlace
Write a function to interlace 2 strings.
interlace("abc", "123") -> "a1b2c3"
interlace("bed", "ras") -> "breads"6. Find second occurrence
Write a function to find the position of the 2nd “a” in a string.
find2nd("banana") -> 3
find2nd("happy birthday") -> 127. Add “na”
Write a function to add a specified number of “na” strings to “ba”.
addNa(0) -> "ba"
addNa(1) -> "bana"
addNa(2) -> "banana"
addNa(3) -> "bananana"8. Powers of 2
Write a function to calculate the sum of powers of 2.
sumPowers(0) -> 0
sumPowers(1) -> 0+1 = 1
sumPowers(2) -> 0+1+2 = 3
sumPowers(3) -> 0+1+2+4 = 7
sumPowers(4) -> 0+1+2+4+8 = 15