Logical Operators

Understanding Logical Operators

  • Logical Operators are used in programming to compare two or more expressions.
  • They return a Boolean value, either True or False based on the condition.
  • The main logical operators are AND, OR, and NOT.

Logical AND Operator

  • AND operator returns True only if both expressions under comparison are True.
  • For example, if A and B are two expressions, “A AND B” is True only if both A and B are True.

Logical OR Operator

  • OR operator returns True if any one of the expression is True.
  • For example, if A and B are two expressions, “A OR B” will be True if either A or B or both are True.

Logical NOT Operator

  • NOT operator reverses the logical state of the operand.
  • If a condition is True, NOT operator will make it False and if it is False, it will change it to True.

Applying Logical Operators in Computer Programs

  • Logical operators are used in conditional statements, such as the if statement. They help control the flow of a program based on conditions.
  • For example, if a computer program has two conditions A and B, these conditions can be combined using logical operators to create complex tests, like “if (A AND B)” or “if (A OR B)”.
  • Common use cases could include checking multiple criteria for a decision, combining tests, or inverting a condition to check for something not happening.

Precedence Rules

  • Precedence of logical operators is: first NOT, then AND, and lastly OR.
  • They can, however, be manipulated using parentheses to override their default precedence.

Truth Tables

  • Truth tables are used to represent the result of all the possible combinations of inputs in logical operations.
  • They’re particularly useful when dealing with multiple conditions or complex statements.

Pitfalls and Errors

  • Order of processing logical operations is crucial. Ensure you have a good understanding of operator precedence.
  • Do not confound equal operator “==” with the logical AND “&&” or logical OR “**   **” operators.
  • Learn to test for negative logic as well. NOT operator could be quite beneficial in some scenarios.

To test your understanding of these concepts, try creating and solving some truth tables yourself, in addition to analysing the flow of a code snippet with logical operators.