C# Eval Expression Supported Operators

In a programming language, operators are special symbols such as +, -, ^, etc., that perform some action on operands. The Z.Expressions.Eval library manages almost all C# operators and it also respects the C# precedence rules of operators.

• Operators allow the processing of primitive data types, and objects.
• They take as an input one or more operands and return some value as a result.

For example, operators are the signs for adding, subtracting, multiplication, and division like +, -, *, /, and the operations they perform on the integers and the real numbers.

Types

Below is a list of the different types of operators which are most commonly used.

Arithmetical

In C#, the arithmetical operators are +, -, *, etc., and they perform mathematical operations such as addition, subtraction, and multiplication respectively on numerical values, and the result is also a numerical value.

Here are some examples of arithmetic operators and their effects.

public static void Example1()
{
    List<string> expressions = new List<string>()
    {
        "a + b",
        "a - b",
        "a * b",
        "a / b",
        "a % b",
    };

    foreach (var expression in expressions)
    {
        var result = Eval.Execute<int>(expression, new { a = 10, b = 5 });
        Console.WriteLine("{0}: {1}", expression, result);
    }
}

Let's run the above code and you will see the following output.

a + b: 16
a - b: 4
a * b: 60
a / b: 1
a % b: 4

Logical

Logical operators or you can say Boolean operators take Boolean values and return a Boolean result (true or false).

The following table contains the logical operators in C# and the operations that they perform.

Let's consider the following simple examples of logical operators.

public static void Example2()
{
    List<string> expressions = new List<string>()
    {
        "a && b",
        "a || b",
        "a ^ b",
        "!b",
        "true || b",
        "(5 > 7) ^ (a == b)"
    };

    foreach (var expression in expressions)
    {
        var result = Eval.Execute<bool>(expression, new { a = true, b = false });
        Console.WriteLine("{0}: {1}", expression, result);
    }
}

Comparison Operators

Comparison operators are used to comparing two or more operands. C# supports the following comparison operators.

• greater than (>)
• less than (<)
• greater than or equal to (>=)
• less than or equal to (<=)
• equality (==)
• difference (!=)

The following example shows the usage of comparison operators.

public static void Example3()
{
    List<string> expressions = new List<string>()
    {
        "a > b",
        "a < b",
        "a == b",
        "a != b",
        "a >= b",
        "a <= b"
    };

    foreach (var expression in expressions)
    {
        var result = Eval.Execute<bool>(expression, new { a = 10, b = 6 });
        Console.WriteLine("{0}: {1}", expression, result);
    }
}