Hiring guide for Ada Engineers

Ada Developer Hiring Guide

Ada is a high-level, structured, statically typed programming language that was developed in the late 1970s by the U.S. Department of Defense (DoD) to supersede over 450 programming languages used for its embedded computer systems. Named after Ada Lovelace, often credited as the world's first programmer, it was designed with an emphasis on software engineering principles and strong typing. The language is renowned for its safety-critical support and real-time capabilities which make it extensively used in defense systems, aviation, and space technology. Its most recent standard version is Ada 2012 which introduced contract-based programming features among other improvements. The development and evolution of Ada are maintained by ISO/IEC JTC1/SC22/WG9 working group.

Ask the right questions secure the right Ada talent among an increasingly shrinking pool of talent.

First 20 minutes

General Ada app knowledge and experience

The first 20 minutes of the interview should seek to understand the candidate's general background in Ada application development, including their experience with various programming languages, databases, and their approach to designing scalable and maintainable systems.

How would you declare a variable in Ada?
In Ada, a variable is declared using the keyword 'declare'. The syntax is 'variable_name : data_type := initial_value;'. For example, 'declare x : Integer := 5;'.
What are the basic data types in Ada?
The basic data types in Ada are Integer, Float, Character, Boolean, Duration, and String.
Describe the difference between a procedure and a function in Ada.
In Ada, a procedure is a subprogram that performs an action but does not return a value, while a function is a subprogram that returns a value.
How would you handle exceptions in Ada?
In Ada, exceptions are handled using the 'begin', 'exception', and 'when' keywords. You would write your risky code in a 'begin' block, and handle exceptions in an 'exception' block using 'when'.
What are the different types of loops available in Ada?
Ada provides several types of loops including 'while' loops, 'for' loops, and 'loop' (infinite) loops. These loops can also be controlled with 'exit' and 'next' statements.
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What you’re looking for early on

Does the candidate have a strong understanding of Ada language and its syntax?
Has the candidate demonstrated problem-solving skills during the interview?
Is the candidate able to communicate effectively and explain complex ideas clearly?
Does the candidate have experience with software development methodologies such as Agile or Scrum?

Next 20 minutes

Specific Ada development questions

The next 20 minutes of the interview should focus on the candidate's expertise with specific backend frameworks, their understanding of RESTful APIs, and their experience in handling data storage and retrieval efficiently.

Describe the difference between a task and a protected object in Ada.
In Ada, a task is a type of concurrent unit of execution, similar to a thread. A protected object is a type of data structure that provides mutually exclusive access to its data, ensuring data integrity in concurrent environments.
How would you use a package in Ada?
In Ada, a package is used to group related declarations. It's defined using the 'package' keyword and can be used in a program by 'with' keyword. For example, 'with MyPackage; use MyPackage;'.
What is the use of 'with' and 'use' clauses in Ada?
'with' clause is used in Ada to import a package, and 'use' clause is used to avoid prefixing the package name before accessing its members.
How would you implement polymorphism in Ada?
In Ada, polymorphism is implemented using tagged types and abstract types. A tagged type can have multiple implementations, and an abstract type is a tagged type that cannot be directly instantiated.
Describe the difference between 'in', 'out', and 'in out' parameters in Ada.
'in' parameters are read-only and cannot be modified, 'out' parameters are write-only and their initial values are not defined, and 'in out' parameters can be read from and written to.
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The ideal back-end app developer

What you’re looking to see on the Ada engineer at this point.

At this point, a skilled Ada engineer should demonstrate strong problem-solving abilities, proficiency in Ada programming language, and knowledge of software development methodologies. Red flags include lack of hands-on experience, inability to articulate complex concepts, or unfamiliarity with standard coding practices.

Digging deeper

Code questions

These will help you see the candidate's real-world development capabilities with Ada.

What does this simple Ada code do?
with Ada.Text_IO; use Ada.Text_IO;
procedure Hello is
    Put_Line ('Hello, world!');
end Hello;
This is a simple Ada program that prints 'Hello, world!' to the console.
What will be the output of this Ada code snippet?
with Ada.Text_IO; use Ada.Text_IO;
procedure Show_Sum is
    A, B, Sum : Integer;
    A := 5;
    B := 7;
    Sum := A + B;
    Put_Line (Integer'Image(Sum));
end Show_Sum;
This Ada code snippet adds two integers, 5 and 7, and prints the result, 12, to the console.
What does this Ada code do, which manipulates an array?
with Ada.Text_IO; use Ada.Text_IO;
procedure Array_Sum is
    type Array_Type is array (1 .. 5) of Integer;
    Array_Var : Array_Type := (2, 4, 6, 8, 10);
    Sum : Integer := 0;
    for I in Array_Var'Range loop
        Sum := Sum + Array_Var(I);
    end loop;
    Put_Line (Integer'Image(Sum));
end Array_Sum;
This Ada code declares an array of 5 integers and calculates the sum of those integers. It then prints the sum, 30, to the console.
What does this Ada code do, which involves tasking and concurrency?
with Ada.Text_IO; use Ada.Text_IO;
procedure Simple_Task is
    task T is
        entry Start;
    end T;
    task body T is
        accept Start;
        Put_Line ('Task T is running.');
    end T;
end Simple_Task;
This Ada code defines a task T with an entry point Start. The main program calls T.Start, which triggers the task T to run concurrently and print 'Task T is running.' to the console.

Wrap-up questions

Final candidate for Ada Developer role questions

The final few questions should evaluate the candidate's teamwork, communication, and problem-solving skills. Additionally, assess their knowledge of microservices architecture, serverless computing, and how they handle Ada application deployments. Inquire about their experience in handling system failures and their approach to debugging and troubleshooting.

How would you implement data encapsulation in Ada?
In Ada, data encapsulation is implemented using packages. The package specification defines the public interface, and the package body hides the implementation details.
What are discriminants in Ada?
Discriminants in Ada are similar to parameters for a type. They allow the creation of variant records, where the structure of the record can change depending on the value of the discriminant.
Describe the difference between a limited type and a private type in Ada.
In Ada, a limited type is a type that can only be assigned at the point of declaration and cannot be copied or compared. A private type is a type whose full definition is hidden from the clients.

Ada application related

Product Perfect's Ada development capabilities

Beyond hiring for your Ada engineering team, you may be in the market for additional help. Product Perfect provides seasoned expertise in Ada projects, and can engage in multiple capacities.