Classroom Notes: Unit 1.2 Selection and Logic in flowcharts

Arithmetic operators commonly used in programming:

• Addition (+) → Adds two values.
  Example: 5 + 3 = 8
• Subtraction (-) → Subtracts one value from another.
  Example: 10 - 4 = 6
• Multiplication (*) → Multiplies two values.
  Example: 7 * 2 = 14
• Division (/) → Divides one value by another.
  Example: 20 / 5 = 4
• Modulus (%) → Returns the remainder after division.
  Example: 17 % 5 = 2 (since 17 divided by 5 is 3 with remainder 2)
• Increment (++) → Increases a value by 1 (used in languages like C, Java, C++).
  Example: x++ if x = 5 → x = 6
• Decrement (--) → Decreases a value by 1.
  Example: y-- if y = 8 → y = 7

Comparison (relational) operators commonly used in programming:

• Equal to (==) → Checks if two values are equal.
  Example: 5 == 5 → true
• Not equal to (!=) → Checks if two values are not equal.
  Example: 7 != 3 → true
• Greater than (>) → Checks if the left value is larger than the right.
  Example: 10 > 6 → true
• Less than (<) → Checks if the left value is smaller than the right.
  Example: 4 < 9 → true
• Greater than or equal to (>=) → Checks if the left value is larger than or equal to the right.
  Example: 4 >= 3 → true
• Less than or equal to (<=) → Checks if the right value is larger than or equal to the left.
  Example: 3 <= 3 → true

Boolean (logical) operators used in programming:

• AND (&& or and) → Returns true if both conditions are true.
  Example: (5 > 2) && (10 > 3) → true
• OR (|| or or) → Returns true if at least one condition is true.
  Example: (4 > 7) || (8 > 2) → true
• NOT (! or not) → Reverses the Boolean value.
  Example: !(5 > 2) → false

A selection statement is a programming construct that lets the program choose which block of code to execute based on a condition.

Some of the common types of selection statements are:

• if → Executes code if condition is true.
• if-else → Executes one block if true, another if false.
• if-else if ladder → Checks multiple conditions in sequence.
• switch → Selects one option from many based on a variable's value.

In short, selection statements are used as decision making tools that control the flow of a program.

1. Check if a number is positive
2. Check if a student passed (Passing marks is 40 out of 100)
3. Check if a number is even or odd
4. Compare two numbers and say which one is greater