What is Type: Definition and 952 Discussions

In programming languages, a type system is a logical system comprising a set of rules that assigns a property called a type to the various constructs of a computer program, such as variables, expressions, functions or modules. These types formalize and enforce the otherwise implicit categories the programmer uses for algebraic data types, data structures, or other components (e.g. "string", "array of float", "function returning boolean"). The main purpose of a type system is to reduce possibilities for bugs in computer programs by defining interfaces between different parts of a computer program, and then checking that the parts have been connected in a consistent way. This checking can happen statically (at compile time), dynamically (at run time), or as a combination of both. Type systems have other purposes as well, such as expressing business rules, enabling certain compiler optimizations, allowing for multiple dispatch, providing a form of documentation, etc.
A type system associates a type with each computed value and, by examining the flow of these values, attempts to ensure or prove that no type errors can occur. The given type system in question determines what constitutes a type error, but in general, the aim is to prevent operations expecting a certain kind of value from being used with values for which that operation does not make sense (logic errors). Type systems are often specified as part of programming languages and built into interpreters and compilers, although the type system of a language can be extended by optional tools that perform added checks using the language's original type syntax and grammar.

View More On Wikipedia.org
Recent contents Top users
  1. Jacinta

    Does my blood type collaborate with my personality?

    So I was arguing with this person online about something and then all of a sudden they decide to throw out something along the lines of "you're so cold-blooded". They were correct. In school we were always taught your average body temperature is 37 Degrees Celsius but mine is like 36. Therefore...
  2. T

    I Is simulation considered a type of quantitative analysis?

    Hello, I've been asked to talk about a time where I have used quantitative analysis. I once used simulation of the solar system to find out more about things like close approaches, and Gladmans criteria I was wondering if simulation is considered a quantitative method of analysis and if the...
  3. O

    Gaussian type integral (but not a standard form)

    When working a proof, I reached an expression similar to this: $$\int_{-\infty}^{\infty} \frac{\mathrm{e}^{-a^2 x^2}}{1 + x^2} \mathrm{d}x$$ I've tried the following: 1. I tried squaring and combining and converting to polar coordinates, like one would solve a standard Gaussian. However...
  4. DaveC426913

    B Is the trefoil knot truly unknottable or is there a way to simplify it?

    I was watching a video online about something completely different, but in the background I saw a computer monitor displaying an object similar to this. Can this be topologically reduced to a simpler shape? Such as a simple one-, two- or three-hole doughnut? Or is it an irreducibly complex...
  5. D

    MATLAB Matlab code for a Gillespie type reaction (model) with wolves and elk.

    Copy and paste if you want to use any of this code. Its a simple iteration of converting biomass of elk into new wolves. % example for ODE and Gillespie % one reversible reaction b1 = .033; bo = .00047; a1 = .0022; ao = .00055; Aini = 5168; Bini = 34; %% Basic ODE simulation dt = 0.01...
  6. Gabriela

    I What's the name of this type of function?

  7. L

    Work and Forces -- Not understanding this basic friction on a ramp type of problem

    The question that puzzled me during lecture! : A block is pushed so that it moves distance L up a ramp (incline angle q ) at constant speed. If there is friction, the magnitude of the work done on the block by friction…(ramp is up and leftwards) A. is mgsinqL. B. is less...
  8. Bizmuth

    Is there a stellar type that would make Firefly possible?

    The Firefly universe (as I understand it) is a large number of planets orbiting a very large star with a wide habitable zone. Of course, to make that work, the star would also have to be reasonably stable and not emit lethal levels of radiation. Is there a stellar class that could, even in...
  9. G

    Minimize the sum of Type I and Type II errors

    Homework Statement Given X_1,\dots,X_n a simple random sample with normal variables (\mu, \sigma^2). We assume \mu is known but \sigma^2 is unknown. The hypothesis is \begin{cases} H_0: & \mu=\mu_0 \\ H_1: & \mu=\mu_1 > \mu_0 \end{cases} Determine the rejection region R...
  10. A

    MBTI type (Myers-Briggs Type Indicator) -- Jung Typology Personality Test

    I always keep on taking the MBTI and I get INTP. What is everyone else's MBTI? http://www.humanmetrics.com/cgi-win/jtypes2.asp << Mentor Note -- INTP = Introverted iNtuitive Thinking Perceiving >>
  11. A

    Is a Ring Crimp Terminal the Best Connection Tip for TCK Type K?

    Hi, I need to connect my TCK type K to the brass component which has working temperature approximately 200degC. I intend to drill/tap a hole in the brass (M3) and fix TCK to it with a bolt. I wonder whether using ring crimp terminal as the tip for the termocouple would be a good option...
  12. W

    Schools Applying to schools without the type of engineering I want?

    I'm a rising high school senior with an interest in industrial engineering. Although I'm aware that plenty of people graduate with degrees completely different from what they wanted to do in high school, industrial engineering is what I want to major in right now. Industrial engineering...
  13. BillTre

    Are Prions Involved with Type 2 Diabetes?

    This Science news article discusses mouse research which indicates prion involvement. Prion like clumps of islet amyloid polypeptide are found in humans with type 2 diabetes. When injected into healthy mice amyloid clumps formed and the mice developed diabetic symptoms. Prions are mis-folded...
  14. L

    Looking for advice on a type of product I want to develop

    Hi! I have an idea for a product that i want to invent / make. I know nothing about materials / science. I came across this website and thought I would post my question. I am looking for a material OR a combo of materials that can withstand the SUN (from the outside) - it will have a lot of...
  15. M

    MHB Show Triangle ABC Similarity Type Independence of B,C

    Hey! :o Let K,L be circles with exactly two intersection points S and A. Let $C\in L$ and $B\in K$ with $C,B\neq S,A$. I want to show the similarity type of the triangle ABC is independent of the place of B and C. Could you explain to me what I am supposed to show?
  16. T

    Identify the type of support at each location along the beam

    Homework Statement I have problem with the carried over factor in photo 670 . It's not stated the type of support at point A , B , C , D and E . But , at joint at A and E , it's fixed support because the author use distribution factor of 1 at A and E ( in photo 669) Homework EquationsThe...
  17. P

    Curious effect in Command Prompt "Type" command

    I create a text file using notepad or any other text editor or word processor. There is a hyphen in the file. If I then display that file using the TYPE command in the Command Prompt then that hyphen gets replaced with a lower case u with a GRAVE symbol over it. What's going on? No big deal...
  18. Z

    Type of answer: 10% of 20% of 30%

    Homework Statement What is10% of 20% of 30%? Hi, I have a confusion: If we are asked to find 20% of 50, then it would be: 20/100 * 50, (Note answer won’t be in percentage) [/B] Now 10% of 20% of 30% should be: 10/100 * 20/100 * 30/100 =0.006 The above answer should not be in percentage. Am...
  19. ChrisVer

    Arrays/vectors without knowing type

    Hi, Is it possible to declare an array list or vector in C++ without knowing beforehand the type of objects it may contain? (in fact it may contain any kind of object) For example if I have the following classes (maybe there are some mistakes overall, but my main concern is how to deal with the...
  20. W

    Programs Help choosing a type of engineering-- unclear on differences

    I've been researching different types of engineering and since some of them are pretty similar, I'm having trouble understanding the difference between them. Fields I'm looking into: Industrial engineering, systems engineering, manufacturing engineering, operations research, supply chain...
  21. Const@ntine

    B What type of equation is this?

    Hi! I recently came across this pic: Problem is, I have no clue how to tackle this. I didn't find it in any textbooks or anything, so I don't know where to look for it. Sorry if it's a "weird" question, but it's been eating at me for a couple of hours now. I saw it categorized as "high...
  22. J

    I Can a Spectrometer be used to detect material type?

    Hi, I don't know much about science of spectrometry, but I am working on a project where i need to detect and differentiate between different types of material types, and I was just wondering if I can use an Spectrometer such as Desktop Spectrometry Kit v3 (...
  23. T

    Biology What type of career areas work with BCIs?

    Hi! I'm interested in learning more about BCIs and the different types of career areas associated with it. I've have a interest in learning about them for commercial use/interaction with everyday objects and was wandering what type of degree/science studies this type of topic/thing... Thanks...
  24. A

    A Einstein manifolds as asymptotic background spacetimes in Type IIB string theory

    On page 30 of the notes (https://arxiv.org/abs/1501.00007) by Veronika Hubeny on The AdS/CFT correspondence, we find the following: So far, we have been describing just one particular case of the AdS/CFT duality, namely (3.3). There are however many ways in which the correspondence can be...
  25. Mahesh Dahal

    Which type of busbar is this (220kV)?

  26. M

    What Type of Cam Does a Four Arc Design Describe?

    I am trying to determine what type of cam this is from the various cam diagrams but they don't really help as they all seem very similar. I have a simple four arc cam, so a base circle/arc, a nose circle/arc and an arc on one side tangent to the nose and base arcs, and another of slightly...
  27. S

    Type of circuit -- What would you call this?

    Homework Statement Homework Equations No relevant equations The Attempt at a Solution Trying to figure out what type of circuit this is. As far as i can tell its just a circuit with voltage, inductors, and resistance and a switch Only thing is i don't know what type of circuit this would be...
  28. E

    Returning an array of generic type

    This is a homework problem, so I have to follow some stipulations, namely: The problem is, I have no idea how to get a method to return a generic-type array. Because of type erasure, I can't create an instance T[] of a generic array, empty or otherwise. The only way I was able to do it was...
  29. M

    I Types of Regions in Calculus 3

    It's calculus 3 question My textbook does a horrible job at explaining the differences between Type I and Type II regions for z =ƒ(x,y) functions, and Type 1, Type 2, and Type 3 for B=ƒ(x,y, z). And when integrating over these "D" regions, the method of integration doesn't really seem to be...
  30. T

    Difficulty with band type brake

    Homework Statement [/B] What is the brake torque and the needed force to stop the drum. Photo of problem: https://gyazo.com/5c814dc6791b29362cc2835dacf7005a Data not on photo: Max pressure is 0.7MPa and friction coefficient is 0.2. Homework Equations T=(P1-P2)D/2 p=2P/bD dP-fdN=0 dN=Pdθ The...
  31. sas3

    Help Identify Rock in Western Upper Michigan

    I came across this rock and it just seemed out of place and was wondering if anyone could help identify it. I am in the Western Upper michigan area.
  32. Noisy Rhysling

    Food for thought: What type of alien have you NOT seen ....

    ... in a syfy story that you think would be fun? I was imaging a race of quasi-crabs who entered the Empire of Man after having met only one human, an Oxford don type who gave them some ... interesting ... ideas of what the rest of the human race was like.
  33. T

    The Best Orifice Type for highest pressure drop

    I'm an engineering student, one of my task is to search the best orifice type for pressure drop. I have no idea which one would it be since I believe that the beta ratio is the one that would determine the best orifice for pressure drop.
  34. A

    I What is the type of field is exerted by argon plasma?

    when argon gas is transformed to plasma by an electric current, what is the type of field (electric field or magnetic field) and will that field have any effect on electric machinery put in the plasma container like a hand drill or something? assuming we can have argon plasma with high pressure...
  35. H

    What type of mathematical function is this? Thanks :)

    John lives in Dallas and his kitchen has a room temperature of about 70 degrees fahrenheit. He wanted to make her family some cookies for dessert, so he preheated her oven to 350 degrees fahrenheit. In 1 minute, the oven was 135 degrees fahrenheit. In 2 minutes, the oven was about 200 degrees...
  36. enosis_

    Problem with BitLocker Recovery - can't type letters

    I have a Dell Latitude E5510 running Windows 10 pro. My BitLocker password stopped working and I'm locked out. I found the BitLocker Recovery key - but I can't type ANY letters into the field. <Editor note: Key removed. Not essential to the problem.>
  37. BiGyElLoWhAt

    Java What is this type of button called

    I want to make a time selector, basically. I want to have an hour and minute selector, but I want there to be an up arrow and down arrow to cycle through 1-12 and another one for minutes 0-59. Does anyone know what this is called?
  38. kolleamm

    Storing a string in a created obj type

    Homework Statement How can I store String s in X x_obj [] = new X [100] ;2. What I tried I tried x_obj [0] = s; But it didn't work. I know there are easier ways but this is how I have to do it. Thanks in advance
  39. Pyrus

    What type of sensor does this faucet use?

    This photo attached is an automatic tap. It doesn't seem to have Infrared sensor. Then, which type of sensor is it... Just wondering :p
  40. B

    How can you identify the type of gun by the sound it makes?

    how can you identify the type of gun by the sound it makes ? Like if you had a recording of a gun shot but you Can't see the gun and you can find the bullet.
  41. M

    I Determining the type of interaction

    Hi everyone, I have the following question When a positive pion interacts with a proton, a kaon can be produced, along with another strange particle, as shown in this equation \pi^++\textrm{P}\longrightarrow \textrm{K}^++\textrm{X} Circle the type of interaction shown...
  42. Kernul

    Proofs of the four type of intervals

    Homework Statement Verify that if an interval is bounded it must be one of the four following types: ##(a, b)##, ##[a, b]##, ##(a, b]##, or ##[a, b)##. Homework EquationsThe Attempt at a Solution I don't quite get what I should actually prove here. Do I have to see if, for ##A \subseteq S##...
  43. Vitani11

    What type of charges in currents produce a magnetic field?

    Homework Statement Is a current that produces a magnetic field always going to be either an electron or a proton?
  44. G

    B What is the name of this type of fraction

    Take the fractions 2/5 and 4/10. 2/5 cannot be simplified further without converting the integers into decimals. I need to know the name of the 2/5 fraction. Maybe it's called irreducible form or something like that. Let me give another example, of 1/3, 3/9, or 33/99 only 1/3 is irreducible...
  45. mattyboson12

    Picking an element type for FEA

    When choosing between a 2D 4-node quadrilateral element and 8-node for FEA stress analysis, why is the 8 node option preferred? I understand it has much more flexibility with different shapes due to the central mid node but are there any other reasons?
  46. M

    What Bearings Suit a Shaft with Varying Loads and Diameters?

    I have to select bearings for the shaft using standard bearings catalogue depending on the calculated load. In my shaft I calculate the loads and its 425 and 375 N in point A and B. I should need to choose now what kind of bearings use and also using the diameter of the shaft that its dA=dB=...
  47. Likith D

    B What type of spectrum is a rainbow?

    maybe it is emission spectrum of the sun but, seems continuous... unlike few distinct lines of the hydrogen emission spectrum...few images i just checked about it are similar to absorption spectrum...then maybe difraction could have made emission spectrum seem so or maybe not... Well I am very...
  48. PsychonautQQ

    Identifying type of field extension

    Homework Statement Let [ S] = {2^(1/n) | for all n in the natural numbers}, is Q[ S] algebraic? finite? simple? separable? Homework EquationsThe Attempt at a Solution I believe it is algebraic because every element of [ S] will be a root of x^n-2, and every element of Q is obviously algebraic...
  49. wolram

    New Supersonic Bi-Plane Airplane: Is It Realistic?

    This is a supersonic plane with a bi plane layout Date: March 19, 2012 Source: Massachusetts Institute of Technology Summary: A researcher has come up with a concept that may solve many of the problems that grounded the Concorde. An assistant professor of aeronautics and astronautics, says the...
  50. moenste

    Doped semiconductor material: identify n- p- type

    Homework Statement You are given a small slice of doped semiconductor material but you do not know whether it is n-type or p-type Explain with the aid of a diagram the physical principles of an investigation which would enable you to identify the type. 2. The attempt at a solution I searched...
Back
Top