Questions tagged [data-types]

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3answers
138 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
99 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
97 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
222 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 ...
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1answer
111 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:[] -- ...
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1answer
142 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 ...
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6answers
1k 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
135 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 ...
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1answer
83 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 ...
2
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1answer
488 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
325 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 : ...
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2answers
241 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
222 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
140 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
69 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? ...
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2answers
121 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
150 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 ...
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2answers
111 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
747 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 ...
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5answers
12k 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
487 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 ...
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1answer
157 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 ...
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16answers
11k 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 ...
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1answer
152 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 ...
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2answers
579 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 ...
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1answer
69 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
390 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
29 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
249 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: ...
3
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2answers
620 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 ...
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5answers
8k 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 ...
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3answers
3k 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 ...
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1answer
732 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 ...
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4answers
668 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
546 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 ...
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1answer
398 views

What are some intuitions that support calling the Maybe constructor in Haskell “Just”?

The intuition of an optional type like Maybe Int is that either there is no Int (thus, there's Nothing there) or that there is some Int; there is something there. It makes sense to me that we call the ...
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1answer
2k views

Best Practice for Potentially Large JSON Numeric Vaues

I raised this issue on the github project for RazorJam.Insightly, where as you can see it turns out that an error is occurring because for the particular items that I am retrieving and deserialising ...
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9answers
4k views

What do relational databases gain by setting a predefined data type for each column?

I'm working with an SQL database right now, and this has always made me curious, but Google searches don't turn much up: Why the strict data types? I understand why you'd have a few different data ...
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1answer
238 views

When were unsigned types first introduced in programming languages?

Recently I learned that standard Fortran does not support unsigned integers. Fortran is a language with a very long history. I suppose that when Fortran was first designed, there simply wasn't any ...
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8answers
87k views

Use empty string, null or remove empty property in API request/response

When transferring object through an API, as in schemaless JSON format, what is the ideal way to return non-existent string property? I know that there are different ways of doing this as in examples ...
3
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2answers
384 views

How to test abstract data types that I implement myself?

How does one even approach testing an abstract data type? I mean, besides the normal (supposed) way of doing unit tests, where you mock the collaborators, feed them in the class to test, together ...
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4answers
380 views

Subtyping without adding state or behavior - Bad Practice?

Observation There are many Exception subtypes that don't have any added state or behavior. For example, ClosedByInterruptException code. Question Why is subtyping without adding state or behavior "...
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1answer
75 views

Where to format number strings? Server or browser?

I am storing numbers in my database without formatting (e.g., 1434587). But I need a formatted string in the UX (e.g., $1,434,587). Is it better to store the raw number AND the formatted value in the ...
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2answers
777 views

Is a linked list considered a collection of objects?

Sedgewick's Algorithm 4ed says Several fundamental data types involve collections of objects. Specifically, the set of values is a collection of objects, and the operations revolve around ...
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3answers
432 views

Primitive types vs fundamental types?

I have heard both "fundamental types" and "primitive types" being used. Is there a difference in what the two phrases are referring to?
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2answers
519 views

What is the proper way to implement an abstract data type in C?

In his book Patterns in C, Adam Petersen describes using a pointer to a struct, which is declared in a header file, to create a first-class abstract data-type: /* Customer.h */ /* A pointer to an ...
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2answers
3k views

Can an interpreted statically typed language be considered type safe?

First let me explain what is my understanding of the terms statically typed language and type safety: Statically typed language: a language that does not allow you to change the type of a variable at ...
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7answers
2k views

Why does Java have primitives for different size numbers?

In Java there are primitive types for byte, short, int and long and the same thing for float and double. Why is it necessary to have a person set how many bytes should be used for a primitive value? ...