Socratic programming

A sampling of real-world problems, ranging from the simple to the complex, whose solutions are discovered by the students.

Problem class Square

• Input: real number x
• Output: the square of x

Problem class ArrayAverage

(Use ArrayTotal() from Friday. We declared it as

public static double ArrayTotal(double[] arr) {
  ...
}

• Input: array of real numbers
• Output: average of numbers in array
• Example input:

  +----+----+----+----+----+
  | 96 | 87 | 99 | 56 | 92 |
  +----+----+----+----+----+
  

• Example output: 430 / 5 = 86.0

Problem class AbsoluteValue

• Input: real number x
• Output: absolute value of x

Problem class IsEven

• Input: integer n
• Output: 1 for even n, 0 for others

Problem class Exponentiate

• Input: real number x and integer n
• Output: the nth power of x
• Example input:

  x == 2.5, n == 2
  

• Example output: 6.25

Problem class ArrayFind

• Input: array of integers, integer n
• Output: index of first occurrence of n in array
• Example input:

  +----+----+----+----+----+----+
  | 56 | 17 |  2 | 42 |  5 | 97 |        n == 42
  +----+----+----+----+----+----+
  

• Example output: 3

Problem class ArrayReplace

• Input: array of characters, character old, character new
• Output: same array, with every occurrence of old replaced with new
• Example input:

  +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  | 'I' | ' ' | 'l' | 'i' | 'k' | 'e' | ' ' | 'P' | 'G' | 'S' | 'S' |
  +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  
  old == 'k', new == 'v'
  

• Example output:

  +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  | 'I' | ' ' | 'l' | 'i' | 'v' | 'e' | ' ' | 'P' | 'G' | 'S' | 'S' |
  +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  

Problem class IntToBinary

• Input: integer n
• Output: array of integers giving bits of n, ordered as in Homework 1
• Example input: 17
• Example output:

  +---+---+---+---+---+
  | 1 | 0 | 0 | 0 | 1 |
  +---+---+---+---+---+
  

Problem class MatrixAdd

• Input: two-dimensional arrays of reals a and b
• Output: sum of a and b
• Example input:

       +----+----+         +----+----+
       |  5 |  8 |         |  6 | -5 |
       +----+----+         +----+----+
  a == |  0 | -1 |    b == |  2 |  1 |
       +----+----+         +----+----+
       |  2 |  5 |         |  0 |  0 |
       +----+----+         +----+----+
  

• Example output:

       +----+----+
       | 11 |  3 |
       +----+----+
       |  2 |  0 |
       +----+----+
       |  2 |  5 |
       +----+----+
  

Problem class IsSubstring

• Input: two arrays of characters str and query
• Output: index of first location in str where all of query matches characters of str
• Example input:

         +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  str == | 'I' | ' ' | 'l' | 'i' | 'k' | 'e' | ' ' | 'P' | 'g' | 'h' |
         +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
  
           +-----+-----+-----+
  query == | 'o' | 'v' | 'e' |
           +-----+-----+-----+
  

• Example output: 3

Problem class ArrayMoveToEnd

• Input: array of integers, integer n
• Output: same array, but with every instance of n. shifted to array's end
• Example input:

  +----+----+----+----+----+----+----+
  |  5 |  8 | 42 |  1 |  3 |  5 |  6 |
  +----+----+----+----+----+----+----+
  
  n == 5
  

• Example output: 430 / 5 = 86.0

  +----+----+----+----+----+----+----+
  |  8 | 42 |  1 |  3 |  6 |  5 |  5 |
  +----+----+----+----+----+----+----+