Questions tagged [data-types]

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54 views

Integer type for data structure index

I have implemented an append-only tree data structure as a class in C++20. Internally it uses std::vector<Node<T>> where Node<T> contains an int parent_index and T payload. A node ...
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1answer
34 views

Time limit or built-in flush of HashTable entries

Is there a standard data type which is a struct or a table or a dictionary which will always delete objects that are older than t minutes? for example if I want to make sessions expire after 60 ...
0
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1answer
111 views

What is the purpose of types which may be replaced by others?

In Kotlin or Java we have many different types: integer, byte, double, long, float, string, character, etc. But one can use an integer instead of byte, and a double instead of an integer. Why we need ...
2
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6answers
578 views

What is the viability of engineering an integral type with values ranging from -1 to 254? Do types like this even exist?

In software engineering, often developers will utilize three different states of a signed integer, as a trilean: This tends to be quite typical: -1 - Represents something akin to a null pointer, as in ...
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1answer
151 views

Should all structures be ADTs?

Is there any specific category an ADT must be in? I'm struggling to find out how best to represent objects in the program for example: As a record: struct Person { int age }; Or as an ADT: struct ...
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6answers
867 views

Do any programming languages use types as values? Would there be any point?

The standard way that types are handled in programming languages that have such a concept, is that they are: removed entirely at compile time and are just used to determine memory layout, function ...
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1answer
88 views

What is the Difference Between Float and Double Data Types? [duplicate]

Apart from the memory size of both data types, I want to know any other differences and also want to know when we use float and when we use double?
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3answers
140 views

Is it called “composition” if we are using primitive data types?

The following is an example of "composition": public class Car { Engine engine; // Engine is a class } But is it still called "composition" if we are using primitive data ...
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0answers
35 views

Is there a simpler way to monitor changes to a piece of data, and disallow removing the data from monitoring?

I'm working on an algorithm visualizer for sorting algorithms. Give it a (user-submitted) sorting algorithm, hit run, it'll generate a random list of integers and show you what the algorithm looks ...
2
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2answers
130 views

Why do some languages decouple operations from data type?

This is a pretty difficult question to frame. But I'll try my best. In some languages, data types are decoupled from the operations they can perform, while in other languages like JavaScript they are ...
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2answers
155 views

Is there a difference between abstract data type and interface?

From what I understand, an abstract data type is basically some data and what we are allowed to do with that data (ex. a list with a set of data and an attribute size and the functions get(), set(), ...
3
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3answers
454 views

Why am I getting complex errors even with simple C++ code?

I started to play with C++ recently. One of the difficulties I have quite often is when the compiler tells that there is an issue with the types: more often than not, those compiler errors look ...
4
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3answers
313 views

How to visualize a Stream object (and some other data types)?

I want to make a small programming tutorial which will have a number of images visualizing various data types, but I am not sure how to draw these images of the data types. Assume that I have a ...
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3answers
155 views

What goes into a computer deciding how many memory locations to assign for specific data types in C?

I have learned file memory management and some very simple CPU assembly for manual memory manipulation. Still, I feel like there is a gap in my knowledge when it comes to modern, complex computers, ...
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1answer
102 views

Is there a name for this pattern of composing a type safe return type from different levels of nested related entities?

I have a problem in my app where I have many entities that can all reference each other in different ways. For example, I have a Job (e.g. build house) that I might assign to a team called "Plumbers" ...
3
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1answer
102 views

A size-type vs index-type conundrum

Suppose I'm writing C or C++ code which deals with... ok, let's make it citizens in a state. In this state, citizens have numeric id's (not strings - numbers); and for reasons of performance, or ...
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5answers
537 views

How do B-Trees used in databases sort data based on different fields?

I know majority of databases uses B-Trees, and I can see how using a balanced binary tree will give fast sort times, for ordering by ID or whatever else the primary key is; but how are databases able ...
0
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1answer
137 views

How do Haskell Lists Desugar?

So, I was wondering about how Haskell's lists are implemented. I looked it up, and found this: data [] a = [] | a : [a] So I get that you can write lists like this if you want to: a:b:c:[] -- ...
0
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1answer
151 views

What is the correct way to dynamically declare the type of a variable (in Java)? [closed]

Disclaimer: I previously posted this on Stack Overflow, but it seems that perhaps that was not the correct site for the question. If this is still not the correct site, please let me know. I'm ...
12
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6answers
2k views

why aren't the platform specific integer types in C and C++ (short, int, long) deprecated?

TL;DR: Why isn't everybody screaming, "Don't use short, int, and long unless you really need to, and you very likely don't need to!" I understand that, in theory, by using the types short, int, and ...
2
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0answers
153 views

Data Types Based Database

I was wandering if there exists some kind of database that organises data based on some declared type rather than tables or collections. I'll try to explain better with an example. Let's say I have ...
1
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1answer
114 views

When is it a good idea to include explicit type declarations in Kotlin?

In Kotlin, specifying the return types of functions and the types of variables is usually optional but can be optionally included. I've encountered a few benefits of including them: It sometimes ...
3
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1answer
1k views

Using Null/None/Nil vs empty data types

This question is more coding style related which is why this question is asked here. I'm new to Python, coming from PHP. I've been looking through Python style guides & code examples, I've ...
3
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3answers
397 views

Language design : How to type higher order functions parameters?

I'm trying to design a theoretical programming language and I'm facing a problem with high order functions. The language is strong-typed, so the way to define a standard function is like so : ...
0
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2answers
382 views

What are the “scalar fields” and “composite fields” in JAVA?

Need to understand the below definition, from the protobuf tutorial: mergeFrom(Message other): (builder only) merges the contents of other into this message, overwriting singular scalar fields, ...
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4answers
309 views

Can int16_t be easier on the processor then int?

I know that the compiler and architecture of a processor also have a role to play in this. But this is more of a "can it" rather then a "does it" question. I have already tried to research this, but ...
2
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2answers
205 views

What to do with data types with lots of connections in a UML class diagram

I have a Pose data type, consisting of x, y, and rotation values. This being a robotics application, the Pose data type is used in about a dozen places throughout the application. Connecting all ...
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0answers
75 views

Convert between enum and discriminated union

Is there a software pattern (or some recommended guidelines) for how to convert between enum values and discriminated unions? Or more specifically: project a discriminated union onto its enum case? ...
1
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2answers
124 views

Reading problem of object-oriented concept about the book “Object-oriented software construction 2/e”

I've been learning object-oriented concept from this book, and stuck in a specified concept in the middle of chapter 6. Because with no brief explaining beforehand, no one could understand my ...
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1answer
201 views

How float data type stores number greater than 2^23? As Mantissa is only 23 bits

Can someone explain how floating point numbers are stored in C, as for 32-bit float, 1 bit is parity, 23 bits for mantissa and 8 bits for exponent. So for numbers greater than 2^23(still in the float ...
3
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2answers
114 views

What is the term for the side on which a variable type is written in a given language?

In the case that a type is specified, it could be on the left (before) or the right (after) of the variable name. For example, C, C# and Java have the type specified before the variable: int num = 5;...
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2answers
1k views

How the value of the integer variable is stored in a memory by bytes/bits?

In C program I'm doing below stuff int x = 4; Let us assume integer has 2 bytes in this case. So my question here is the variable x will hold two bytes that mean 16 bits. So here how the value 4 ...
44
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5answers
14k views

How do variables in C++ store their type?

If I define a variable of a certain type (which, as far as I know, just allocates data for the content of the variable), how does it keep track of which type of variable it is?
3
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3answers
977 views

How to store external numeric IDs - as strings or as integers?

Every now and then we programmers need to communicate with external systems (not under our own control). It's frequent that in such cases we need to keep track of some sort of identifiers that these ...
1
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1answer
263 views

Differentiating Between ASCII and Unicode in File Spec

I am developing against a file spec that lists the data type for certain fields as CHAR(<length>) The spec is for a fixed width flat file. In most cases, possible values to populate the fields ...
58
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16answers
12k views

How should I store “unknown” and “missing” values in a variable, while still retaining the difference between “unknown” and “missing”?

Consider this an "academic" question. I have been wondering about about avoiding NULLs from time to time and this is an example where I can't come up with a satisfactory solution. Let's assume I ...
0
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1answer
164 views

Does primitive obsession apply to columns of tables in database?

For example, in a Student object, in order to avoid primitive obsession, I should change public class Student{ public String name; public int age; } into public class Student{ public ...
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0answers
119 views

Subclassing numeric types for safety

I'm writing something that handles length units, say, metres and feet. I don't want to accidentally convert between them (trying to avoid something like the Mars Climate Orbiter crash). I'd like to ...
8
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2answers
600 views

Only one number type in language design

I am currently learning about compiler construction and language design and I am thinking about what native datatypes I want to support in my language. Now there is a whole lot of languages that make ...
0
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1answer
76 views

Not sure how to setup my data for a waypoint system

I have a system i've written on paper and am trying to write this into C# in a easy to use manner. I want a series of connected waypoints (where by waypoints can be connected to any number of other ...
3
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5answers
398 views

Is there a practical benefit to using the smallest datatype possible?

In C# (and other languages), we can define a numerical variable as a short, an int, or a long (among other types), mostly depending on how big we expect the numbers to get. Many mathematical ...
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0answers
31 views

React JS: Mixing data types for one state property

In the spirit of minimising state I always have a desire to mix data types for a given state property. For instance, if I were creating a React page that rendered a list of items that could either be ...
3
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1answer
1k views

When writing a Qt application is good practice to ALWAYS prefer Qt function implementations, data types, and classes when they are available?

I'm just starting out with Qt and I really want to try and keep my application as separated from Qt as possible in case I decide to use a different toolset later, but at the same time don't want to ...
3
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1answer
251 views

Built-in type AND value checking of parameters?

Does any programming language have a concept of checking the type and value of a given parameter without adding an explicit if (myParam < 0) { .. } within the function? A pseudocode example: ...
4
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2answers
831 views

Which layer for custom type (DDD)

If I have a custom type (or maybe an enum) like for ex. a Range: Public Class Range Sub New(minimum As Single, maximum As Single) Me.Minimum = minimum Me.Maximum = maximum ...
3
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5answers
11k views

Why are Python sets and dictionaries not ordered by default?

I understand the difference between ordered and unordered sets, and I understand why for many purposes, we don't need ordered sets. But all set operations are still possible on ordered sets, and sets ...
1
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3answers
4k views

Which is a more efficient way of storing data in a database using Objects or strings (Database design)

Which method is better to store the data in a database and why? Here is a restaurant example. I'm using a SQL database and JSON to communicate with the database. Imagine each row is a column in a ...
1
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1answer
1k views

Are C++ types classes? [closed]

I am trying to understand if C++ types are classes, like in Python for example. Otherwise what datatype is the type itself? E.g. int a = 10 what is int? Is just a token label used by the compiler to ...
13
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4answers
681 views

About my database date datatype crusade: Valid? Worthwhile? Does anyone else feel it?

I spend a lot of time answering SQL questions over on SO. I frequently come across queries of this ilk: SELECT * FROM person WHERE birthdate BETWEEN '01/01/2017' AND '01/03/2017' SELECT * FROM ...
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2answers
723 views

Why do data types like int and float have maximum values

in C#, an int data type has a maximum value of 2,147,483,647 and a float maximum value is 340282300000000000000000000000000000000 what causes these data types to have maximum values, where do those ...