How to reactively check for an error after an operation fails, and how a subsequent successful operation clears the error state.

ID: 1189

See: Handling Errors 
				
					using uCalcSoftware;

var uc = new uCalc();
// Trigger a syntax error
uc.EvalStr("1 +");

// Check the error state after the fact
if (uc.Error.Code != ErrorCode.None) {
   Console.WriteLine($"Error detected: {uc.Error.Message}");
} else {
   Console.WriteLine("Success!");
}

// Perform a successful operation, which clears the error state
uc.EvalStr("1 + 1");
if (uc.Error.Code == ErrorCode.None) {
   Console.WriteLine("Previous error was cleared by successful operation.");
}
				
			
Error detected: Syntax error
Previous error was cleared by successful operation.
Explore 600+ other examples
				
					#include <iostream>
#include "uCalc.h"

using namespace std;
using namespace uCalcSoftware;

int main() {
   uCalc uc;
   // Trigger a syntax error
   uc.EvalStr("1 +");

   // Check the error state after the fact
   if (uc.Error().Code() != ErrorCode::None) {
      cout << "Error detected: " << uc.Error().Message() << endl;
   } else {
      cout << "Success!" << endl;
   }

   // Perform a successful operation, which clears the error state
   uc.EvalStr("1 + 1");
   if (uc.Error().Code() == ErrorCode::None) {
      cout << "Previous error was cleared by successful operation." << endl;
   }
}
				
			
Error detected: Syntax error
Previous error was cleared by successful operation.
Explore 600+ other examples
				
					Imports System
Imports uCalcSoftware
Public Module Program
   Public Sub Main()
      Dim uc As New uCalc()
      '// Trigger a syntax error
      uc.EvalStr("1 +")
      
      '// Check the error state after the fact
      If uc.Error.Code <> ErrorCode.None Then
         Console.WriteLine($"Error detected: {uc.Error.Message}")
      Else
         Console.WriteLine("Success!")
      End If
      
      '// Perform a successful operation, which clears the error state
      uc.EvalStr("1 + 1")
      If uc.Error.Code = ErrorCode.None Then
         Console.WriteLine("Previous error was cleared by successful operation.")
      End If
   End Sub
End Module
				
			
Error detected: Syntax error
Previous error was cleared by successful operation.
Explore 600+ other examples