Comparison & Logical Operators

Syntax

==  !=  <  >  <=  >=   &&  ||  !

Examples

int a = 5, b = 3;

Console.WriteLine(a == b);  // false
Console.WriteLine(a != b);  // true
Console.WriteLine(a > b);   // true
Console.WriteLine(a <= b);  // false

int age = 25;
bool hasId = true;

if (age >= 18 && hasId)
{
    Console.WriteLine("Entry allowed");
}

bool isWeekend = false;
bool isHoliday = true;

if (isWeekend || isHoliday)
{
    Console.WriteLine("No work today");
}

bool isBanned = false;
if (!isBanned)
{
    Console.WriteLine("Access granted");
}

string a = "hello";
string b = "hel" + "lo";

Console.WriteLine(a == b);         // true - compares content
Console.WriteLine(a.Equals(b));     // true - same result

object x = "hello";
object y = "hello";
Console.WriteLine(x == y);  // true for string literals (interned)

Best practices

• Take advantage of short-circuit evaluation: put null checks first in && expressions (obj != null && obj.Value > 0) to avoid a NullReferenceException
• Trust == for string comparisons in C# - unlike Java, it compares content because string overrides the equality operator
• Wrap multi-condition logical expressions in parentheses for clarity, even when not strictly required by operator precedence
• Use string.Equals(a, b, StringComparison.OrdinalIgnoreCase) instead of .ToLower() == .ToLower() for case-insensitive comparisons - it avoids unnecessary allocations

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation