-
Random Number Generation–Functions–STRUCTURED PROGRAMMING Course Notes
Random Number Generation rand(); a C++ Standard Library function that generates an unsigned integer between 0 and RAND_MAX (a symbolic constant defined in the <cstdlib> header file). The function prototype for the ‘rand’ function is in <cstdlib>. rand()%6 to produce integers specifically in the range 0 to 5, for a dice-rolling game, for example, we use the modulus operator(%). This is called scaling. The number 6 is called the “scaling factor”. We would then shift the range of numbers produced by adding 1 to our previous result. ex: (1 + rand() % 6 ) srand() the function ‘srand‘ takes an unsigned integer argument and seeds the ‘rand‘ function to produce…
-
Functions–STRUCTURED PROGRAMMING Course Notes
Functions Experience has shown that the best way to develop & maintain a program is to construct it from small, simple pieces or components. This technique is called “divide & conquer”. Declare and use functions to facilitate the design, implementation, operation, and maintenance of large programs. Functions (aka methods, procedures, sub-routines) allow us to modularize a program by separating its tasks into self-contained units. We can use a combination of provided library functions or create out own functions, known as user-defined, or programmer-defined functions. The statements in function bodies are written only once but can be reused from perhaps several locations in a program and are hidden from other functions.…
-
Data Members, ‘set’ Functions, & ‘get’ Functions–C++ Notes (C Plus Plus Notes)
Variables declared in a functions body are local variables, and can be used only from the point of their declaration in the function to the immediately following closing right brace (}). When a function terminates, the values of its local variables are lost. A local variable must be declared before it can be used in a function. A local variable cannot be accessed outside the function in which it’s declared. Data members normally are private. Variables or functions declared private are accessible only to member functions of the class in which they’re declared, or to friends of the class. When a program creates (instantiates) an object of a class, its…
-
Functions, & O.O.P.–C++ Notes (C Plus Plus Notes)
Functions Performing a task in a program requires a function! The function hides from its user the complex tasks that it performs. C++ Functions–A function is a block of code which only runs when it is called. Data, known as parameters, can be passed into a function. Functions are used to perform certain tasks, or actions, and they are important for reusing code: Define the code once, and use it many times. C++ provides some pre-defined functions, such as ‘main()‘ which is used to execute code. But you can also create your own functions to perform certain actions. C++ Functions consist of two parts: Declaration–the functions name, return type, and…
-
More Notes!!! [Ruby Programming Language Notes]
Global Variables–Variable References Lecture $–Use this sign to create a global variable in Ruby. Ex: def say_hello $message = “hello globe” end say_hello p $message # => “hello globe” More Methods! object_id can be used to see what memory location a particular variable points to . ex: variable.object_id => 7018903, or whatever number the computer assigned. Initializing an Array! *(Variable References Lecture) So we know that ‘arr = [ ]‘ will create a new empty array. We can use ‘arr = Array.new()‘ to initialize an array of a certain length by passing the length we want into the parameter (argument). ex: Array.new(3) #a new array with 3 elements => [nil,…
-
Sorting &Swapping Elements, & Bubble Sort Algorithms!!! [Ruby Programming Language Notes]
Sorting & Swapping Elements, & Bubble Sort Algorithms!!! Algorithm a sequence of actions to take! Sorting Algorithms Swapping Elements Operation: array = [“a”, “b”, “c”, “d”] #let’s swap “a” & “b” temp = array[0]; #save a copy of the first ele array[0] = array[1]; #overwrite the 1st ele with the 2nd ele array[1] = temp; #overwrite the 2nd ele with the 1st ele copy p array # => [“b”, “a”, “c”, “d”] This works but is a bit messy. Ruby has a clean shortcut (that also works in Python!)! array = [“a”, “b”, “c”, “d”] #let’s swap “a” & “b” array[0], array[1] = array[1], array[0] p array # => [“b”,…
-
Symbols!!! [Ruby Programming Language Notes]
Symbols in Ruby Symbols are an additional data type, similar to strings, but different. str = ” “ strings are wrapped in quotes. Symbol = : symbols begin with a colon. Ex: str = “hello # the string sym = :hello # the symbol p str.length # => 5 p sym.length # => 5 p str[1] # => “e” p sym[1] # => “e” p str == sym # => false #Lesson…A string is DIFFERENT from a symbol! Strings are mutable (can be changed, or mutated). Symbols are immutable (can never be changed, or mutated). Because strings are mutable, they are always stored in a new memory location (even if…
-
More Common Enumerable Methods!!! [Ruby Programming Language Notes]
More Common Enumerable’s .all?–return ‘true’ when all elements result in true when passed into the block. Ex: p [2,4,6].all? { |el| el.even? } # =>(returns) true Ex: p [2,3,6].all? { |el| el.even? } # => false .any?–return ‘true’ when at least one element results in true when passed into the block Ex: p [3,4,7].any? { |el| el.even? } # => true Ex: p [3,5,7].any? { |el| el.even? } # => false .none?–return ‘true’ when no elements result in true when passed into the block. Ex: p[1,3,5].none? { |el| el.even? } # => true Ex: p[1,4,5].none? { |el| el.even? } # => false .one?–return ‘true’ when exactly one element results in…
-
Array-Giving Enumerables!!! [Ruby Programming Language Notes]
array.map–allows us to take in an array and modify it a certain way. (Returns a new array!) (This can let us skip the step of shoveling a desired result into a new array[].) arr = [“a”, “b”, “c”, “d”] Old way: new_arr = [ ] arr.each { |ele| new_arr << ele.upcase + “!” } print new_arr puts Output: [“A!”, “B!”, “C!”, “D!”] New way with .map: arr = [“a”, “b”, “c”, “d”] #(.map is still an enumerable, so when we call it we have to pass in a block.) #This block accepts the element as well, like .each. new_arr = arr.map { |ele| ele.upcase + “!” } #In the block…
-
Hashes–Another Data Structure!!! [Ruby Programming Language Notes]
Hashes! (Another data structure) An array allows us to have a single variable, or location, to store & group a lot of data. (Allows for organization!) An array was the first data structure we learned about. [ ]–An array is made up of elements, organized by indices. But sometimes we may need a different organization when building a program. That’s why we have HASHES!!! A hash is made up of values stored by keys. (A key “unlocks” the corresponding value.) { }–curly braces are used to represent a hash in Ruby. (This can be assigned to a variable.) In a hash, data comes in a pair, (a ‘key value’ pair).…