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INF.04ProgrammingLogic

Relational and Logical Operators: How to Compare Data?

Understand how comparison operators work and how to combine conditions using AND, OR, and NOT. Essential knowledge for control statements.

December 25, 20252 min read
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Relational and Logical Operators

For a program to make a decision, it must first be able to compare data. Relational (comparison) operators are used for this. If we want to check multiple conditions at once, we use logical operators. These are the heart of every if statement and loop.

[Image showing comparison and logical operators symbols in code]

1. Relational Operators (Comparisons)

Used to check the relationship between two values. The result is always a boolean: true or false.

2. Logical Operators

Allow combining multiple comparisons into one complex expression.

CechaOperatorName
&&ANDTrue if both are true
||ORTrue if at least one is true
!NOTReverses the boolean value

Common Mistakes and Pitfalls

Confusing = with ==

The single `=` is for assignment. The double `==` is for comparison. Using `=` inside an `if` usually leads to logical errors.

Quiz: Check your knowledge

What is the result of: (5 > 2) || (3 < 1) ?

What next?

  1. Memorize truth tables for AND, OR, and XOR operators.
  2. Practice writing conditions checking numeric ranges.
  3. Learn the difference between == and === in JavaScript.

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