Unit 4 - Variables, Conditionals, and Functions
comparison operators
<, >, <=, >=, ==, != indicate a Boolean expression
variable
A placeholder for a piece of information that can change.
local variable
A variable that can only be accessed from a specific portion of a program
global variable
A variable whose scope covers the entire program, it can be used and updated by any part of the code. Its scope is typically derived from the variable being declared (created) outside of any function, object, or method.
Logic Error
An error in a program that makes it do something other than what the programmer intended.
Boolean expression
An expression that evaluates to either true or false
string
Any sequence of characters between quotation marks.
evaluate
Expressions are evaluated to produce a single value.
logical operator
NOT, AND, and OR, which evaluate to a Boolean value.
Conditionals
Statements that only run under certain conditions.
if-statement
The common programming structure that implements "conditional statements".
expression
a combination of operators and values that evaluates to a single value
function call
a command that executes the code within a function
Boolean value
a data type that is either true or false.
pseudocode
a description of the actions of a program or algorithm, using a mixture of English and informal programming language syntax
procedure
a named group of programming instructions that may have parameters and return values. Also referred to as a "function".
function
a named group of programming instructions. Also referred to as a "procedure".
expression
a programming statement that can consist of a value, a variable, an operator, or a procedure call that returns a value.
Iteration
a repetitive portion of an algorithm which repeats a specified number of times or until a given condition is met.
algorithm
a step-by-step procedure for solving a problem
conditional statement
affect the sequential flow of control by executing different statements based on the value of a Boolean expression.
assignment operator
allows a program to change the value represented by a variable
selection
determines which parts of an algorithm are executed based on a condition being true or false
Many conditionals example - if this compound condition or that compound condition
if (((condition 1) && (condition2)) || ((condition3) && (condition4))) { // Run this code } Parentheses are needed for: 1) the entire compound conditional statement 2) the first compound conditional statement 3) the second compound conditional statement 4) All individual conditions.
Compound conditional AND example
if ((condition 1) && (condition2) ) { //Run this code }
Compound conditional OR example
if ((condition1) || (condition2)) { //Run this code }
if-else-if statement syntax (App Lab)
if (condition) { // Run this code } else if (condition) { // Run this code } else { // Run this default code } The if-else-if statement is used when you want to have levels of conditions. You can add as many else if statements as you need. "Check one condition first. If it is false, check another condition", etc.
if-else statement syntax (App Lab)
if (condition) { // Run this code } else { // Run this default code }
if statement syntax (App Lab)
if (condition) { //Run this code }
concatenation
joins together two or more strings end-to-end to make a new string.
arithmetic operators
part of most programming languages and include addition, subtraction, multiplication, division, and modulus operators.
MOD
performs the modulo operation between two numbers. It is represented by the % sign. The modulo operation finds the remainder. For example, 5 MOD 2 or 5%2 returns the value of 1. The remainder of 5 divided by 2 is 1.