3.6. Data Types: Logical Operators

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3.6. Data Types: Logical Operators

Logical operators are fundamental in programming logic. They allow you to make comparisons between values, resulting in a boolean (true or false) value. These operators are used in control structures such as loops and conditionals to determine the flow of a program. Let's discuss the most common logical operators: AND, OR, and NOT.

AND operator

The logical operator AND, also known as "AND", returns true if both operands are true. For example, if we have two conditions, A and B, the expression "A AND B" will be true only if A and B are true. If any one of the conditions is false, the entire expression is false.

For example, in a program that checks whether a user is of legal age and has a driver's license to determine if the user can drive, both conditions must be true. If the user is of legal age, but does not have a driver's license, or if he has a driver's license, but is not of legal age, he will not be able to drive.

OR operator

The logical operator OR, also known as "OR", returns true if at least one of the operands is true. Using the previous example, if we have two conditions, A and B, the expression "A OR B" will be true if A is true, B is true, or both are true. The expression will be false only if both conditions are false.

For example, in a program that checks that a user has a credit card or enough money in their account to make a purchase, the purchase can be made if any of these conditions are true. If the user does not have a credit card and does not have enough money in the account, he will not be able to make the purchase.

NOT operator

The logical operator NOT, also known as "NOT", inverts the value of an operand. If the operand is true, NOT will make it false and vice versa. This operator is useful for inverting a condition.

For example, in a program that checks if a user is not logged in to display a welcome message, the condition "NOT logged in" will be true if the user is not logged in and false if the user is logged in.

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Combination of Logical Operators

Logical operators can be combined to form more complex expressions. For example, you can verify that a user is of legal age and has a driver's license or parental permission to drive. In this case, the expression would be "(age >= 18 AND hasCarteira) OR hasPermissaoPais".

It is important to remember that the AND and OR operators take precedence over the NOT operator. This means that in an expression like "NOT A AND B", the AND will be evaluated first, so the expression will be equivalent to "NOT (A AND B)". If you want the NOT to be evaluated first, you must use parentheses, as in "(NOT A) AND B".

In summary, logical operators are a crucial part of programming logic. They allow you to do complex comparisons and control the flow of your program. Understanding how they work is critical to becoming an effective programmer.

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103.7. Data Types: Conditional Structures