C# Operators: Arithmetic, Comparison, Logical and more

A look at the various C# operators and what they do, from arithmetic to logic this is a complete C# operator list with operator overloading.

An operator is an element that is applied to one or more operands in an expression or statement. These are typically arithmetic or logical operators used for addition, subtraction, multiplication and division, or comparison. We will also look at changing the behaviour of operators for custom classes and structs. This process is referred to as operator overloading.

C# Operator List

The most common of the operators are the arithmetic and logic operators. These will be very familiar to you if you know other programming languages or mathematics.

Arithmetic Operators

Logic Operators

Increment and Decrement Operators

Relational Operators

Assignment Operators

Other Operators

C# Operator Overloading

In C#, operators can be overloaded as well as methods, a technique that allows custom data types to be manipulated in the same way as a normal data type.

Let's say you create a bank account class, for simplicity, it will only contain a balance and holder name.

public class bankAccount
{
  decimal balance;
  string holdersName;
}

public class Program
{
  static void Main()
  {
    bankAccount testAccount1 = new bankAccount();
    bankAccount testAccount2 = new bankAccount();

    testAccount1.balance = 10.0;
    testAccount1.holdersName = "Bob Smith";

    testAccount2.balance = 20.0;
    testAccount2.holdersName = "Jane Doe";
  }
}

If you wanted to add testAccount2 to testAccount1 you may be tempted to try:

testAccount1 = testAccount1 + testAccount2

or even

testAccount1 += testAccount2

You will find that the compiler will not let you add these together as it does not know how to handle the operators for this custom type. We can tell the C# compiler how to add two bank accounts together by overloading the operators.

public class bankAccount
{
  public decimal balance;
  public string holdersName;

  public static bankAccount operator +(bankAccount b1, bankAccount b2)
  {
    bankAccount temp = new bankAccount();
    temp.balance = b1.balance + b2.balance;
    temp.holdersName = b1.holdersName + " and " + b2.holdersName;
    return temp;
  }
}

This will allow the use of the + operator on the bankAccount class. It will return a bankAccount, which contains the sum of the two balances and the two holders names concatenated.

All the other operators can be overloaded in the same way; all you need to do is provide your logic within the method.

testAccount1 = testAccount1 + testAccount2;

/ testAccount1.ballance = 30
/ testAccount1.holdersName = "Bob Smith and Jane Doe"

This is not how bank accounts are merged, but it gives an illustration of how operators can be overloaded for custom data types.