# Parse and Compute Expressions

## Content



The CalcEngine library is represented by the [C1CalcEngine](/componentone/api/services/online-calcengine/dotnet-standard-api/C1.CalcEngine/C1.CalcEngine.C1CalcEngine.html) class which contains an **IEngine** object and provides its interaction with controls. Here, the [IEngine](/componentone/api/services/online-calcengine/dotnet-standard-api/C1.CalcEngine/C1.CalcEngine.IEngine.html) interface defines properties and methods of expression engine. The **C1CalcEngine** class mainly performs two tasks, parsing formula containing strings into Expression objects so that they can be evaluated and evaluating Expression objects to return the result.

To calculate the formula represented by a string, you need to call [Evaluate](/componentone/api/services/online-calcengine/dotnet-standard-api/C1.CalcEngine/C1.CalcEngine.C1CalcEngine.Evaluate.html) method of the **C1CalcEngine** class. It parses the string into an expression, evaluates it and returns the result as shown in the following example:

```csharp
var calcEngine = new C1CalcEngine();
calcEngine.Expression = “1+1”;
var result = calcEngine.Evaluate();
```