C# Ternary Operator (Shorthand if-else) - Complete Guide
Introduction to Ternary Operator
The ternary operator (?:) in C# provides a concise way to write simple conditional statements. It is often called the conditional operator and allows you to choose between two values based on a condition, all in a single line.
It improves code compactness and readability for straightforward cases, but nested or complex ternary expressions should be avoided for clarity.
Basic Ternary Operator Syntax
The ternary operator syntax is: condition ? value_if_true : value_if_false
Example
using System;
namespace TernaryOperatorExample
{
class Program
{
static void Main(string[] args)
{
int number = 10;
string result = (number > 5) ? "Greater than 5" : "5 or less";
Console.WriteLine(result);
int age = 20;
string status;
if (age >= 18)
status = "Adult";
else
status = "Minor";
Console.WriteLine($"Using if-else: {status}");
status = (age >= 18) ? "Adult" : "Minor";
Console.WriteLine($"Using ternary: {status}");
Console.WriteLine($"The number is {(number % 2 == 0 ? "even" : "odd")}");
double price = 99.99;
string message = (price > 100) ? "Expensive" : "Affordable";
Console.WriteLine(message);
bool isEven = (number % 2 == 0) ? true : false;
Console.WriteLine($"Is number even? {isEven}");
int discount = (price > 50) ? 10 : 5;
Console.WriteLine($"Discount: {discount}%");
}
}
}Output
Greater than 5 Using if-else: Adult Using ternary: Adult The number is even Affordable Is number even? True Discount: 10%
Advanced Ternary Operator Usage
The ternary operator can also be used for grading, selecting maximum values, handling null values, and inline expressions. However, readability should always be considered.
Example
using System;
namespace AdvancedTernaryExample
{
class Program
{
static void Main(string[] args)
{
int score = 85;
string grade = (score >= 90) ? "A" :
(score >= 80) ? "B" :
(score >= 70) ? "C" :
(score >= 60) ? "D" : "F";
Console.WriteLine($"Score: {score}, Grade: {grade}");
int x = 10, y = 20;
int max = (x > y) ? x : y;
Console.WriteLine($"Maximum: {max}");
string name = null;
string displayName = (name != null) ? name : "Guest";
Console.WriteLine($"Welcome, {displayName}!");
displayName = name ?? "Guest";
Console.WriteLine($"Welcome, {displayName}!");
int a = 5, b = 10, c = 15;
string comparison = (a < b && b < c) ? "Numbers are in order" : "Numbers are not in order";
Console.WriteLine(comparison);
Console.WriteLine($"Is positive: {IsPositive(-5)}");
Console.WriteLine($"Is positive: {IsPositive(5)}");
string input = "hello";
string processed = (input.Length > 3) ? input.ToUpper() : input.ToLower();
Console.WriteLine(processed);
int value = 7;
var (description, color) = (value % 2 == 0) ? ("even", "blue") : ("odd", "red");
Console.WriteLine($"{value} is {description} and represented by {color}");
}
static string IsPositive(int number) => (number > 0) ? "Yes" : "No";
}
}Output
Score: 85, Grade: B Maximum: 20 Welcome, Guest! Welcome, Guest! Numbers are in order Is positive: No Is positive: Yes HELLO 7 is odd and represented by red
When to Use and Avoid Ternary Operator
The ternary operator is best for simple conditions. Avoid it when logic is complex, involves multiple statements, or side effects, as it can harm readability.
Example
using System;
namespace TernaryBestPractices
{
class Program
{
static void Main(string[] args)
{
int number = 10;
string parity = (number % 2 == 0) ? "even" : "odd";
Console.WriteLine(parity);
int absoluteValue = (number >= 0) ? number : -number;
Console.WriteLine(absoluteValue);
int x = 5, y = 10, z = 15;
string complexResult = (x > y && y < z) ? "Condition 1" :
(x == y || y > z) ? "Condition 2" : "Default";
Console.WriteLine(complexResult);
string betterResult;
if (x > y && y < z)
betterResult = "Condition 1";
else if (x == y || y > z)
betterResult = "Condition 2";
else
betterResult = "Default";
Console.WriteLine(betterResult);
int value = -5;
if (value < 0)
{
Console.WriteLine("Value is negative");
value = Math.Abs(value);
Console.WriteLine("Converted to positive");
}
int counter = 0;
if (counter > 0)
{
Console.WriteLine("Counter is positive");
counter++;
}
else
{
Console.WriteLine("Counter is zero or negative");
counter--;
}
int age = 20;
string canVote = (age >= 18) ? "Yes" : "No";
Console.WriteLine($"Can vote: {canVote}");
}
}
}Output
even 10 Default Default Value is negative Converted to positive Counter is zero or negative Can vote: Yes