INF1021- Algorithmique: Operators and Calculations

• INF1021- Algorithmique discusses operators and calculations

What You Will Learn

• Arithmetic, boolean, and comparison operators
• String manipulation
• Operator precedence and evaluation order

Operators

• Operators are symbol(s) performing operations on one or more values (operands)
• Operands: values or variables on which operators perform operations
• Example: In "5 + 3", 5 and 3 are operands, and "+" is the operator

Operator Types

• Operators can be unary, acting on one operand such as "-x" for negation
• Operators can be binary, acting on two operands like "x + y" for addition
• Operators are linked to data types, functioning with integers, booleans, etc.
• "%" works with numeric types
• "&&" works with booleans

Arithmetic Operators

• Perform calculations
• Apply to two numeric variables, a and b
• Addition: a + b
• Subtraction: a - b
• Multiplication: a * b
• Division: a / b
• Integer Division: a // b
• Exponentiation: a ** b
• Modulo: a % b or a mod b
• Integer Division: a div b
• Absolute Value: abs(a)
• Opposite Value: -a
• Example: -c = b % a (5 % 2) results in c = 1, with 5 divided by 2 leaving a remainder of 1
• d = b div a (5 div 2) results in d = 2, as 5 divided by 2 gives the integer 2
• f = abs(-3) results in f = 3, as the absolute value of -3 is 3
• n = a ** 3 (2 cubed) results in n = 8

Assignment Operators

• Give value to a variable Addition Assignment: a += b
• Subtraction Assignment: a -= b
• Multiplication Assignment: a *= b
• Division Assignment: a /= b
• Modulo Assignment: a %= b
• Equal: a b
• "a += b," where a is 2 and b is 5, results in a being assigned the value of 7
• "b *= 3," where b is 5, results in b being assigned the value of 15

Increment and Decrement Operators

• Increase or decrease variable value (typically by 1)
• a is a numeric variable
• Pre-increment (++variable): ++a
• Post-increment (variable++): a++
• Pre-decrement (--variable): --a
• Post-decrement (variable--): a--
• Example:
• If a = 2, then b = ++a results in a = 3 and b = 3 (pre-increment)
• If b = 3, then c = b++ results in c = 3 and b = 4 (post-increment)

Comparison Operators

• Compare values
• Apply to two variables (a and b) of the same type
• Greater Than: a > b
• Greater Than or Equal To: a >= b
• Less Than: a < b
• Less Than or Equal To: a <= b
• Equal To: a == b
• Not Equal To: a != b or a b
• Example (with a = 2 and b = 5): -"a > b" results in FAUX (false) -"a != b" results in VRAI (true)

Logical Operators

• Combine logical conditions
• Apply to two boolean variables, a and b
• Result of comparison is either VRAI (true) or FAUX (false)
• AND (Conjunction): a ET b or a && b
• OR (Disjunction): a OU b or a || b
• NOT (Negation): NON a or !a

Truth Table

• When variable A is true and variable B is true, the non A and non B column are false
• When variable A is true and variable B is false, the non A column is false and non B Is true
• When variable A is false and variable B is true, the non A column is true and Non B is false
• When variable A is false and variable B is false, the non A and non B column are true

Truth Table

• When variable A is true and variable B is true, the A and B column is true
• When variable A is true and variable B is false, the A and B column is false
• When variable A is false and variable B is true, the A and B column is false
• When variable A is false and variable B is false, the A and B column is false

Truth Table

• When variable A is true and variable B is true, the A or B column is true
• When variable A is true and variable B is false, the A or B column is true
• When variable A is false and variable B is true, the A or B column is true
• When variable A is false and variable B is false, the A or B column is false

Binary Operators

• Binary operators manipulate individual bits
• Left Shift: "a << 1"
• Right Shift: "a >> 3"
• Example:
• a = 4 (00000100 in binary)
• b = 48 (00110000 in binary) -"a << 1" (Shift left by 1) results in a = 8 (00001000 in binary) -"b >> 2" (Shift right by 2) results in b = 12 (00001100 in binary)

String Operators

• Used for alphanumeric strings
• String Concatenation: a + b or a & b
• String Duplication: a * 2
• Example:
• If a = "deux" and b = "variables"
• "c = a + b" results in c = "deuxvariables" -"d = a * 3" results in d = "deuxdeuxdeux"

Operator Overview by Type

• Integer: +, -, *, /, div, mod, **, <, <=, >, >=, ==, !=
• Real: +, -, *, /, **, <, <=, >, >=, ==, !=
• Character: <, <=, >, >=, ==, !=, +, *
• String: <, <=, >, >=, ==, !=, +, *
• Boolean: <, <=, >, >=, ==, !=, ET (AND), OU (OR), NON (NOT)

Operator Precedence (Highest to Lowest)

• Parentheses: ()
• Increment/Decrement: ++, --
• Exponents: **
• Multiplication, Division, Modulo: *, /, %
• Addition, Subtraction: +, -
• Bitwise Shift: <<, >>
• Comparison: ==, !=, <, <=, >, >=
• Logical: ET (AND), OU (OR)
• Assignment: =, +=, -=, *=
• String Operations: +, *