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C# Logical Operators

Logical operators are used to combine conditional expressions and return a boolean result (true or false). They are commonly used in decision-making statements like if and while. The most common logical operators in C# are:

Key Logical Operators

  • && (Logical AND): Returns true if both conditions are true.
  • || (Logical OR): Returns true if at least one condition is true.
  • ! (Logical NOT): Returns true if the condition is false and vice versa.

Example 1: Using Logical AND

// Logical AND Example
int age = 25;
bool hasID = true;

// Condition checks both conditions
if (age >= 18 && hasID) {
    Console.WriteLine("You are allowed to enter.");
} else {
    Console.WriteLine("Entry denied.");
}

Output:

You are allowed to enter.

Code Explanation: The && operator checks if both conditions are true. Since age is greater than 18 and hasID is true, the output confirms entry.

Example 2: Using Logical OR

// Logical OR Example
bool hasKey = false;
bool knowsPassword = true;

// Only one condition needs to be true
if (hasKey || knowsPassword) {
    Console.WriteLine("Access granted.");
} else {
    Console.WriteLine("Access denied.");
}

Output:

Access granted.

Code Explanation: The || operator checks if either condition is true. Since knowsPassword is true, access is granted even though hasKey is false.

Example 3: Using Logical NOT

// Logical NOT Example
bool isRaining = false;

// Negate the condition
if (!isRaining) {
    Console.WriteLine("It's a sunny day!");
} else {
    Console.WriteLine("Bring an umbrella.");
}

Output:

It's a sunny day!

Code Explanation: The ! operator negates the value of isRaining. Since isRaining is false, the logical NOT makes it true, so the program outputs It's a sunny day!.

Key Takeaways

  • The && operator requires both conditions to be true.
  • The || operator requires only one condition to be true.
  • The ! operator reverses the boolean value of a condition.
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