Expression.Decrement Method (Expression)

// Add the following directive to your file: 
// using System.Linq.Expressions;   

double num = 5.5;

// This expression represents a decrement operation  
// that subtracts 1 from a value. 
Expression decrementExpr = Expression.Decrement(
                            Expression.Constant(num)
                        );

// Print expression.
Console.WriteLine(decrementExpr.ToString());

// The following statement first creates an expression tree, 
// then compiles it, and then executes it.
Console.WriteLine(
    Expression.Lambda<Func<double>>(decrementExpr).Compile()());

// The value of the variable did not change, 
// because the expression is functional.
Console.WriteLine("object: " + num);

// This code example produces the following output: 
// 
// Decrement(5.5) 
// 4.5 
// object: 5.5