💡 Ada Exception Handling-Ada Exception Guide

Example

Defining a custom exception for invalid user input and raising it: declare Invalid_Input : exception; begin if User_Input < 0 then raise Invalid_Input; end if; end;

Scenario

In user input validation, custom exceptions help enforce business rules, such as validating age or monetary values, ensuring that data conforms to expected parameters.

Example

Handling an exception in a nested procedure and propagating it upwards to be handled at a higher level: procedure Process_Data is begin Data_Module.Compute; exception when Data_Error => raise; end Process_Data;

Scenario

In a multi-tier application, lower-level modules handle specific tasks (like data processing), while upper layers handle broader control flow and user interaction, ensuring errors are managed at appropriate system levels.

Example

Using an exception block to handle errors during file operations: begin Open(File, In_File, "data.txt"); exception when Name_Error => Put_Line("File not found."); when others => Put_Line("Unknown error."); end;

Scenario

This is useful in applications dealing with external resources, such as file systems or network connections, where multiple types of errors can occur, needing distinct responses for continuity and user guidance.