C# Academy · Lesson

Comparison and Logical Operators

Combine conditions with comparison and logical operators.

Comparison and Logical Operators is a free C# Academy lesson on CoddyKit — 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, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

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.

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.

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, and the C# Academy course includes 4 lessons in total. 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.

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; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

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.

Can I write and run code in this C# Academy lesson?

Yes. Every C# Academy lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

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