What does assert() method do

Using assert statements can be a valuable technique for identifying program logic errors during runtime, while being easily excluded from production code. An assert statement typically consists of two parts: a boolean expression that represents the expected condition, and a message to be displayed if the condition is not met.

Assertions serve as a means to document your intentions and receive notifications from the debugger in the form of a dialog if those intentions are not fulfilled. They temporarily interrupt the normal execution of the program without terminating the application. The System.Diagnostics class provides the Debug.Assert method, which enables the swift implementation of this functionality. When used in a debug compilation, Assert accepts a boolean condition as a parameter and displays an error dialog if the condition evaluates to false. If the condition is true, the program continues its execution uninterrupted.


When implementing Debug.Assert, it is crucial to ensure that any code contained within the assert statement does not alter the program's output when the assertion is removed. Failing to do so may inadvertently introduce bugs that only manifest in the release version of the program. The following example illustrates this concept.

Debug.Assert (DecrementCounter(cnt) != 0 );

At first look we can say that above code will work properly and brake whenever condition become false. Here every time whenever "DecrementCounter" Counter is called then value of "cnt" will be decremented. When you build the Release version , this call to "DecrementCounter" is eliminated, so the "cnt" does not get updated. Eliminating Call to function will result to bug in the release environment. To avoid such error we can use temporary variable for comparison as shown below.

int Temp= DecrementCounter(cnt); Debug.Assert(Temp !=0);

Assertions hold significant value in large and complex programs, as well as in high-reliability applications. They offer programmers a means to promptly identify mismatched interface assumptions and errors that may arise during code modifications. By employing assertions, developers can efficiently detect and resolve issues related to program logic and ensure the reliability of the software.

To ensure the effectiveness of assertions, it is advisable to avoid incorporating function calls within the assert method. Including function calls may introduce side effects or alter the expected behavior of the program, which can lead to unpredictable results. By adhering to this best coding practice, developers can maintain the integrity of the assertion mechanism and minimize the risk of introducing unintended bugs.


Using assertions appropriately and following recommended coding practices, programmers can enhance the robustness and reliability of their applications, making it easier to identify and rectify potential issues early in the development process.