Before we start conditionals lets review Sequence and Loops
Programming Flow Control Structures: The flow control structure is 3 ways that programers make computers do things.
- Sequence refers to the order a code is written in often called order of events.
- Conditionals Today we look at Conditionals.
- Loops repeated lines of code.
What is a conditional?
Conditions (conditional expressions) are the second of three basic flow control structures in programming. Like sequence, conditions influence a computer program’s decision-making process.
“Condiionals are If, then” Statements
Also known as “if, then” logic statements, conditions enable a computer program to act differently each time it is executed; depending on if an input is evaluated to be either true or false.
In a programming language, conditions are classic “if, then” logic statements and possess both a hypothesis and conclusion.
What is a hypothesis: It is an educated Guess. You predict what will happen (conclusion) based on what you observe.
Hypothesis: If I have the proper ingredients for my sandwich… .
Conclusion: Then I can make my sandwich
Why are conditions important?
Conditional statements are important to any computer program because they enable programmers to develop more dynamic programs. What makes computer programs so great is that they can interact with the user. Without conditions, this type of interaction would be impossible.
Evaluating Conditional Expressions
In order to prepare our peanut butter and jelly sandwich, we had to evaluate ( judge) whether or not the necessary conditions were met as we went through
our algorithm. If any of these conditions were evaluated to be false, then our peanut butter and jelly sandwich could not be made.
The exact same principles apply when using conditions in computer programming:
Simple Conditions: Passwords
A classic example of a simple condition is a password. A password secures your computer and all of your personal information. When a user enters a password, the program needs to evaluate this input, and check whether or not the password entered matches the correct one saved for the user.
If the user input matches the password stored in the database…
…then the user can access their profile and personal information.
A rule is a set of guidelines in a programming language that instruct a computer program what operations to execute or perform. For example, the rule in a password program is to never let users access secured and private data.
Conditions modify programs and are rule breakers, or exceptions, to the rule.
For example, we would create a condition for a password program that would enable specific users to access their secured information.
If a user input matches the password stored in the database…
…then the user can access their secured profile/information.