ALGOL W Developer Hiring Guide

Hiring Guide for ALGOL W Engineers

Ask the right questions to secure the right ALGOL W talent among an increasingly shrinking pool of talent.

ALGOL W is a historical computer programming language, developed in 1966 as a successor to ALGOL 60. It was designed by Niklaus Wirth and Tony Hoare at the International Federation for Information Processing (IFIP) Working Group 2.1. The language introduced several innovative features, including record structures and dynamic arrays, which influenced later languages such as Pascal and C++. Despite its influence, ALGOL W was not widely adopted due to the concurrent rise of FORTRAN and COBOL. Its importance lies primarily in its role as a stepping stone in the evolution of programming languages.

First 20 minutes

General ALGOL W knowledge and experience

The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.

What is the purpose of the 'begin' and 'end' keywords in ALGOL W?

The 'begin' and 'end' keywords in ALGOL W are used to define a block of code. This could be the body of a procedure, a loop, or a conditional statement. The code between 'begin' and 'end' is executed as a single unit.

How would you define a procedure in ALGOL W?

In ALGOL W, you define a procedure using the 'procedure' keyword, followed by the procedure name, a list of parameters in parentheses, and a block of code. For example: 'procedure add(x, y); begin return x + y; end;'

Describe the difference between 'if' and 'case' statements in ALGOL W.

In ALGOL W, 'if' is used when you want to check a condition and execute a block of code if the condition is true. 'Case' is used when you want to check multiple conditions and execute different blocks of code depending on which condition is true.

What are the basic data types in ALGOL W?

The basic data types in ALGOL W are integer, real, boolean, char, and bit. These are used to define the type of values that can be stored in variables.

How would you declare and initialize a variable in ALGOL W?

You can declare and initialize a variable in ALGOL W using the following syntax: 'real x := 5.0;' Here, 'real' is the data type, 'x' is the variable name, ':=' is the assignment operator and '5.0' is the value being assigned.

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What youre looking for early-on

Does the candidate have experience working on large projects or with a team?

This shows that the candidate can work in a team environment and handle the complexities of large projects.

Has the candidate shown an ability to learn and adapt?

This is important as technology and coding practices are constantly evolving, so developers need to be able to keep up with changes.

Does the candidate have experience with code optimization in ALGOL W?

This shows that the candidate can write efficient code, which is important for performance.

Can the candidate effectively communicate their thought process and solutions?

Communication skills are important for team collaboration and for explaining complex technical concepts to non-technical team members.

Has the candidate demonstrated problem-solving skills?

Problem-solving skills are crucial for developers as they will often need to find solutions to complex coding problems.

Does the candidate have a strong understanding of ALGOL W syntax and semantics?

This is important as it shows the candidate's proficiency in the language and their ability to write and understand code.

Next 20 minutes

Specific ALGOL W development questions

The next 20 minutes of the interview should attempt to focus more specifically on the development questions used, and the level of depth and skill the engineer possesses.

What is the purpose of the 'own' keyword in ALGOL W?

The 'own' keyword in ALGOL W is used to declare a static variable. A static variable retains its value between calls to the procedure in which it is declared. This is different from a regular variable, which loses its value once the procedure finishes executing.

How would you handle errors in ALGOL W?

ALGOL W does not have built-in exception handling. Errors must be handled manually by checking for potential error conditions and taking appropriate action. For example, before dividing two numbers, you might check if the denominator is zero and if so, handle the error by not performing the division and displaying an error message.

Describe the difference between 'and' and 'or' operators in ALGOL W.

'And' is a logical operator that returns true if both operands are true. 'Or' is a logical operator that returns true if either or both operands are true.

What are the different types of operators in ALGOL W?

ALGOL W supports various types of operators including arithmetic operators (+, -, *, /, mod, rem), relational operators (=, <>, <, <=, >, >=), logical operators (and, or, not), and assignment operators (:=).

How would you implement a loop in ALGOL W?

You can implement a loop in ALGOL W using the 'for' keyword. For example: 'for i := 1 until 10 do begin ... end;' This will execute the block of code 10 times, with the variable 'i' taking values from 1 to 10.

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The ideal back-end app developer

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

A skilled ALGOL W engineer should possess strong problem-solving skills, extensive knowledge of ALGOL W and its applications, and good communication skills. Red flags could include lack of specific examples when explaining their experience or inability to explain complex concepts clearly.

Digging deeper

Code questions

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

What does this simple ALGOL W code do?

BEGIN INTEGER x; x := 5; PRINT(x); END

This code declares an integer variable 'x', assigns the value 5 to 'x', and then prints the value of 'x' which will be 5.

What will be the output of this ALGOL W code snippet?

BEGIN REAL r1, r2; r1 := 3.14; r2 := 2.0 * r1; PRINT((r2)); END

This code declares two real number variables 'r1' and 'r2'. 'r1' is assigned the value 3.14. 'r2' is assigned the value of 'r1' multiplied by 2. The value of 'r2' is then printed, which will be 6.28.

What does this ALGOL W code do with an array?

BEGIN INTEGER ARRAY a[1:5]; INTEGER i; FOR i := 1 STEP 1 UNTIL 5 DO a[i] := i * i; FOR i := 1 STEP 1 UNTIL 5 DO PRINT((a[i])); END

This code declares an integer array 'a' with 5 elements. It then assigns the square of each index to the corresponding element in the array. It then prints each element in the array. The output will be the squares of the numbers from 1 to 5.

What does this ALGOL W code do with threading?

BEGIN PROCEDURE p; BEGIN INTEGER i; FOR i := 1 STEP 1 UNTIL 10 DO PRINT(i); END; PARBEGIN CALL p; CALL p; PAREND; END

This code defines a procedure 'p' that prints numbers from 1 to 10. It then calls this procedure twice concurrently using the PARBEGIN and PAREND keywords. The output will be the numbers from 1 to 10 printed twice, but the exact order cannot be determined because the two procedure calls are executed concurrently.

What does this ALGOL W code do with a class object?

BEGIN RECORD r(i, j); r.i := 5; r.j := 10; PRINT((r.i)); PRINT((r.j)); END

This code declares a record 'r' with two fields 'i' and 'j'. It assigns the values 5 and 10 to these fields, and then prints the values of these fields. The output will be 5 and 10.

What will be the output of this advanced ALGOL W code?

BEGIN INTEGER PROCEDURE factorial(n); VALUE n; INTEGER n; IF n = 0 THEN factorial := 1 ELSE factorial := n * factorial(n - 1); END; PRINT(factorial(5)); END

This code defines a recursive procedure 'factorial' that calculates the factorial of a number 'n'. It then calls this procedure with the argument 5 and prints the result. The output will be the factorial of 5, which is 120.

Wrap-up questions

Final candidate for ALGOL W role questions

The final few interview questions for a ALGOL W candidate should typically focus on a combination of technical skills, personal goals, growth potential, team dynamics, and company culture.

How would you implement a binary search algorithm in ALGOL W?

A binary search algorithm in ALGOL W could be implemented as follows: 'procedure binary_search(a, x); begin integer l := 1; integer r := upperbound(a); while l <= r do begin integer m := (l + r) div 2; if a[m] < x then l := m + 1; else if a[m] > x then r := m - 1; else return m; end; return 0; end;' Here, 'a' is the sorted array, 'x' is the value to search for, 'l' and 'r' are the left and right boundaries of the search, and 'm' is the midpoint.

Describe the difference between 'pass by value' and 'pass by name' in ALGOL W.

'Pass by value' means that a copy of the argument is passed to the procedure. Any changes to the parameter inside the procedure do not affect the original argument. 'Pass by name' means that the argument is passed as a reference. Any changes to the parameter inside the procedure do affect the original argument.

What are the different ways to pass parameters to a procedure in ALGOL W?

In ALGOL W, you can pass parameters to a procedure by value or by name. Passing by value means that a copy of the argument is passed to the procedure. Any changes to the parameter inside the procedure do not affect the original argument. Passing by name means that the argument is passed as a reference. Any changes to the parameter inside the procedure do affect the original argument.

How would you implement recursion in ALGOL W?

You can implement recursion in ALGOL W by defining a procedure that calls itself. For example, a recursive procedure to calculate the factorial of a number would look like this: 'procedure factorial(n); begin if n = 0 then return 1; else return n * factorial(n - 1); end;'

Describe the difference between a 'procedure' and a 'function' in ALGOL W.

In ALGOL W, a 'procedure' is a block of code that performs a specific task and does not return a value. A 'function' is similar to a procedure but it returns a value.

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ALGOL W application related

Product Perfect's ALGOL W development capabilities

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