C# Academy · Lesson

Comparison and Logical Operators

Combine conditions with comparison and logical operators.

Lesson 2 of 413 steps

Comparison and Logical Operators is a free C# Academy lesson on CoddyKit. This is lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the C# Academy learning path, and your progress syncs across the web and the CoddyKit app. The C# Academy course includes 4 lessons in total.

Comparison Operators

Comparison operators produce a bool: == equal, != not equal, < less, > greater, <= and >=.

using System;

class Program {
    static void Main() {
        Console.WriteLine(5 == 5);
        Console.WriteLine(5 != 3);
        Console.WriteLine(5 > 8);
    }
}

Equality vs Assignment

== compares; = assigns. Mixing them up is a classic bug. C# requires a bool in if, so accidental = usually fails to compile.

using System;

class Program {
    static void Main() {
        int a = 7;
        bool same = (a == 7);
        Console.WriteLine(same);
    }
}

Comparing with Variables

Comparisons work on variables, not just literals. The result is a boolean you can store or print.

using System;

class Program {
    static void Main() {
        int age = 20;
        bool adult = age >= 18;
        Console.WriteLine("Adult: " + adult);
    }
}

Logical AND: &&

&& is true only when both sides are true. It is the logical AND operator.

using System;

class Program {
    static void Main() {
        int age = 25;
        bool ok = age >= 18 && age <= 65;
        Console.WriteLine(ok);
    }
}

Logical OR: ||

|| is true when at least one side is true. It is the logical OR operator.

using System;

class Program {
    static void Main() {
        string role = "admin";
        bool canEdit = role == "admin" || role == "editor";
        Console.WriteLine(canEdit);
    }
}

Logical NOT: !

The ! operator flips a boolean: !true is false and vice versa.

using System;

class Program {
    static void Main() {
        bool loggedIn = false;
        if (!loggedIn) {
            Console.WriteLine("Please log in");
        }
    }
}

Short-Circuit Evaluation

&& stops if the left side is false; || stops if the left side is true. The right side is never evaluated then. This is called short-circuiting.

using System;

class Program {
    static bool Check() {
        Console.WriteLine("Check ran");
        return true;
    }
    static void Main() {
        bool result = false && Check();
        Console.WriteLine(result);
    }
}

Short-Circuit as a Guard

Short-circuiting lets you safely test something only when a prior condition holds, avoiding errors.

using System;

class Program {
    static void Main() {
        string text = null;
        if (text != null && text.Length > 3) {
            Console.WriteLine("Long text");
        } else {
            Console.WriteLine("Skipped safely");
        }
    }
}

Combining Conditions

You can chain many conditions. Use parentheses to make the grouping clear and correct.

using System;

class Program {
    static void Main() {
        int hour = 14;
        bool openNow = (hour >= 9 && hour < 12) || (hour >= 13 && hour < 18);
        Console.WriteLine("Open: " + openNow);
    }
}

Comparisons in Branches

Comparison and logical operators are the heart of if statements that drive program flow.

using System;

class Program {
    static void Main() {
        int score = 82;
        if (score >= 90) Console.WriteLine("A");
        else if (score >= 80) Console.WriteLine("B");
        else Console.WriteLine("C or below");
    }
}

Boolean Results Are Values

A comparison yields a real bool value. You can return it, store it, or print it directly.

using System;

class Program {
    static bool IsPositive(int n) {
        return n > 0;
    }
    static void Main() {
        Console.WriteLine(IsPositive(5));
        Console.WriteLine(IsPositive(-2));
    }
}

Quick Check

Test your grasp of logical operators and short-circuiting.

Answer it in the interactive lesson

Recap

Comparison operators (== != < > <= >=) produce booleans. Logical operators combine them: && (AND), || (OR), and ! (NOT).

Both && and || short-circuit, skipping the right operand when the result is already known. This makes them efficient and useful as safety guards.

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Frequently Asked Questions

Is the “Comparison and Logical Operators” lesson free?

Yes — the full text of “Comparison and Logical Operators” is free to read here on the web. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the C# Academy course, upgrade to CoddyKit PRO. The C# Academy course includes 4 lessons in total.

What will I learn in “Comparison and Logical Operators”?

Combine conditions with comparison and logical operators. You practise C# Academy with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start C# Academy?

No prior experience is required. C# Academy on CoddyKit is structured for beginners through advanced learners, so you can start here or from the beginning and move at your own pace. This is lesson 2 of 4.

How long does the “Comparison and Logical Operators” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

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