C++ Tutorial - 24 - Reading From a File

[@InSpmindss]

you are the best teacher i ever have seen in my life, in real sense ,you teach in the best way , a lot lot more thanks to you for providing such materials

[@cmommsen1]

@rockydasha Re:Basically, bucky is a variable of type ifstream, due to this statement: ifstream bucky; And after this statement: bucky.open(filename); bucky is now "connected" to the user-defined file name contained in filename - in this tutorial, "beefy.txt". Therefore, when you use it with >> (known as the extraction operator), the stream looks in beefy.txt, finds the letters 't', 'h', 'i', and 's', and "streams" them into word. The next letter is a space, so the stream operator terminates.

[@zarigull274]

This link is best to learn programming because before this i had no idea about file handling but know i can describe this frequently thanks

[@Qazqi]

Not sure why you'd prefer character arrays over std::string. Anyway, just read it with while (std::cin >> word) {std::cout

[@jgray110]

Thanks Bucky, finally got a file to read after dozens of other search code attempts because I was afraid I couldn't do this, but I tried it and walla, don't forget to bucky.close after while { }. system{"pause") is operating system dependent so eventually we need to learn OS independent code. These tutorials get an A++

[@rybread5718]

Thank you my good man. I used #include and it worked the same.

[@johnnyc130]

Great tutorials. You are very clear in all of them and dont leave me confused like some other tutorials. I made a program that can open files, and create files to write on.

[@colinrickels201]

i have gone to hell and back looking for a tutorial such as this thank you so much

[@Haris0423lhr]

you look like jesus so no problem for you

[@FastCodeDeveloper]

man you must be the most subscribed programmer-youtuber of all time...

[@keykeyine]

Just as a side note, the way you set this up it's never going to print off the last word in the text file you read in. Not a big deal but I thought it might confuse some people. You just need another cout

[@Digiscat]

If you ARE confused, just think a bit and mess around with the code. It'll help you both understand and remember. If you're like me, cin.getline and the array threw you off. cin.getline is like a more flexible cin >>---- So, in other words, its like he put "cin >> filename[50]"....get it? And if you make the number for the array smaller, that just limit how many characters it can hold. So, -- char file[50] -- can hold up to 51...but if you put file[1], itll only USE 2. (+1 since 0 counts.)

[@sum21chan]

I like ur video!! just wanna remind you, you could press the tab button for go in 5 space (I think) instead of pressing the space 5 times!

[@Jonko192]

good for beginners. only a few tips to improve this program: change system("pause"); to cin.get(); and why using cstdlib? the stuff is already in the iostream library. the best thing to do is put the load stuff into a function and inside the function you put a return statement if the file is not open. dont use exit(exit_failure);

[@Finalfox09]

Thank you this tutorial was a life savior

[@concernedviewer6909]

Just wanna say again, Welcome back Buckey!!!

[@CensSka]

I've got an exam tommorow I'm screwed

[@thinumstoneheart6713]

LMAO same af man

[@informativecontent4778]

mine is tommorrow wish me luck

[@jimmychan9282]

mine is tomorrow

[@ZainiverseCreations]

Mine is tomorrow LOL .. Everyone comes to bucky a day before exam ...

[@Mustafalllica]

mine is tomorrow

[@yomguioim]

you can get an open file box with tiny file dialogs on sourceforge is a single C C++ cross-platform file offering many native dialogs.

[@octav3k]

@Duodecillian 50 is the maximum number of characters that variable can hold. So if you had a filename or word (the variables he defined inside the program) that's longer then 50 characters, only the first 50 would be read by the program.

[@arraybabe8514]

yes, use getline and dont forget to include the string header

[@OnlineMediaCollection]

Just needed this line, *while (iMyFile.good())* LOL. Thanks!

[@thetruereality2]

That wouldn't print anything, it would only work in case of an eof function. I think you meant while(MyFile.good)

[@naimcool36]

@@thetruereality2 hes right "good" is a function

[@Boeing737Channel]

@Yikak4 cin.getline = just like cin >>, just can manipulate it more. It gets the line you enter. (filename,50) is to store what you inputed in filename, and you need to include 50, the char character size.

[@jasperko308]

Solution for programs that couldn't work. You need to select file on the top left hand corner in CODEBLOCK

[@LPSlasher]

3:30, People: keep in mind that using SPACEBAR in an empty line may wreck the code sometimes, don't try it. (in empty lines you should use either TAB or ENTER... Of course you CAN use SPACEBAR after a codeline)

[@MozartTime]

I just needed to refresh my mind about fstream. Loved this , so clear as good.

[@octav3k]

@Silvertide82 You can create a file with Notepad (he did so before running the tutorial) inside the directory where he saved his cpp file. For example, if he had "tutorial.cpp" inside "C:\Users\Greg\C Toturials\", the text file would have to be in the same directory: "C:\Users\Greg\C Tutorials\beefy.txt". I hope that clears it up for you.

[@muhammadbinsaleem8565]

Bro ! May you live happy life...

[@Wingedzephir]

Great you just solved all my problems with this simple example...well done thanks!

[@fernandinhoflor]

Add in the end of while the following expression: if(!bucky.good()) { bucky >> word; cout

[@r3sp3c791]

Couldn't get a think from this one, it was so fast!!!

[@RazRikimaru122]

Hey is there any possible way to make the number from each line in the text file output into an array grid of variables ?

[@razeal113]

its saying that the char string can be up to 50 characters long. ie, he doesn't know the length of the filename ahead of time so he allows for up size 50. if he was worried about extensions (blah/blah2/.../file) might have made it larger, but 50 should do for any file

[@usabnd]

@linglihe ofstream is for output file. it means if you want to change the content of a file.. hope I helped

[@ivaka92]

20 y.o. here :) it was an honest reaction really - stuff until here was easy to comprehend and suddenly lots of commands and info! When i watched it 2-3 more times i got the hang of it... almost :)

[@shidono6786]

are you working now?

[@h8errage]

@shebotnov ofstream enters stuff into a file, and ifstream gets stuff from a file(read a file) i think u can use an fstream object that does both so u never have to ask yourself that question.

[@christophergaspar6520]

anybody who sees this please help, i wrote a code similar to this in my visual studio I then noticed that, when the program is displaying the text file, the last word is not included. even in bucky's program, notice at 6:05 the last word ('C++') is not included. is there a way to fix this I would greatly appreciate your help, thank you

[@Mrlpjo]

i understood after watching the third time... not so confusing as i thought at first..

[@dumacele6724]

so relatable "come on baby",,,exctly how we al talk to our computers when we're in the zone

[@GregVanGorp]

instead of using exit(EXIT_FAILURE); it would be easier to explain "return 1;". For all of you beginning programmers, this returns a value to int main() and signifies that the program did not execute correctly. Both methods work, but for beginning programmers, this is simpler.

[@genjimidou]

After seeing 5 times I finally understand ...xD

[@kotapaka]

Oh...OK. I merely thought of pointing out that learning/knowing C++ and the standard library is probably the easiest step in the world of programming and software (especially reading/writing files). In C++ read/write file operations are made a breeze by the library.

[@octav3k]

Tou can't see the last word because the condition on the while function is put before the body of the function (he used while, not do-while) and each time the program reads a word with "bucky >> word", it moves to the end of that word. After it reads the last word, the function "bucky.good()" becomes false and it doesn't enter the loop again in order to post the variable (word) to the screen. He could have avoided this either by using do-while or through the method described by andreipopescu87.

[@meyerflyer34]

It could be used for storing options in video games and then outputing them with a custom GUI.

[@sumittechkgp]

if you are using EXIT_FAILURE then use return(EXIT_SUCCESS) instead of return 0

[@HarisMalik]

instead of adding cstdlib we can use same code but exit(0) and the program must exit

[@CloakLord]

I am working on a planner I've got it to read the class end line , homework end line , and then the day its due on to the file and read it from the file. Although, I have 4 classes and I don't know how to name the variables in a way where I can have it restate all the homework correctly. I have tried multiple ways and many dead end ideas such as call functions which seemed genius at the time to read it from the file and based on which it is to have the variable be set to that in that call function. I just had an idea to have it read from multiple files based on the class, but seems impractical.

[@CloakLord]

This video helped a lot o.o

[@PaxiKaksi]

But getline eats the last word in your text so........ That is a bit inefficient ?

[@Ishakislife]

Do you do this often? If you do I may continue with programming. Otherwise, I think I may change my Major!! (this online class thing sucks!)

[@andreipopescu87]

to repaire the problem with not showing the last word from bucky's tutorial just delete bucky >> word; from above the while loop and reverse the 2 lines inside de while loop { bucky >> word; cout

[@muhammadfariezdaniel4769]

wah thankyouuu>< I am watching this in 2021

[@2testtest2]

you need a compiler to make you code into a executable. If you wathc thenewboston's C++ tutorial.

[@th3kid13]

hella good tutorial keep it up!

[@reggaemediatv]

Thank you

[@yasirwisal8081]

Hi Bucky, How do you end line if there is a large text file with the string data type and do some calculation from data which is in text file?

[@yougurtbeautiful9895]

Write a function in C++ to write the characters entered through the keyboard into the file“ myfile.txt”, until a '#' character is entered.

[@Mozi111111]

It works great! Thank you!

[@mokab223]

THANKS BRO!! great job !!

[@kottpower]

This is the most difficult tutorial yet.

[@SimpleCookiee]

First time I watched it i thought it was difficult then I took a break, had dinner and thought about t for a while.. Then alll cleared up. I found it a bit confusing you didn't have to specify to C++ that you want the next word.. It actually takes it automatically cuz you did the ~~~ = word.

[@DRDSkidroW]

@SuperiorOnRoblox make sure you placed the exclamation mark in: " if (!test.is_open()){ " that was my problem

[@ChadDrakeTech]

Your videos started off well bu now you just rush through everything.

[@establishment4132]

K then pay more attention

[@kaushikdr]

@@establishment4132 it is kind of fast though

[@sarahbiebah]

Why doesn't line 6 CREATE the file like we have done before? How come this time it needs the file already created? What's different?

[@josephrowell9052]

When I do this, whatever actual file there is, it prints loads of zeros?

[@doerparol]

How can I make the program to store single characters instead of words? Afterwards I would like to process that stored information and count each letter so number of a= 50 b = 46 and so on

[@Vlaxiti]

nice and clear !! thnx

[@anikatahir6146]

Im having this problem that i have to construct a program to read my file where i have to provide choice for the user to select. Like i saved names and roll numbers in my file and now i have to provide option to user to select which roll number's name should be displayed/read....

[@chris7toronto]

Thanks Bucky!

[@EjMacarus]

"and if you don't believe me..."

[@baarbie0786]

So what is the ideal way of reading from a file?

[@awesaatyanta3106]

couldn't you just use like if (!bucky.good()){ return 0; } instead of including another library? it works for me so is there any particular for using the cstdlib for exitting my program ONLY or is it just matter of preferences?

[@Mowteng]

i dont understand how you can go through each loop, where in the code you told C++ that you want the file content separated by space? why is the first cout in the while not the complete content of the file (with a max of 10 chars ofc) ?!?

[@hexmedi]

@HamishWare when you don't specify the directory, it searches for the given file inside of your project folder. at least this is how it works for me

[@TheMohawkNinja]

@linglihe I think that of is Output File, and if is Input File

[@tarBall313]

i'm sorry but i don't understand the word 'getto'. But if it's a bad word (like shit, bad etc.), that's not what I meant. Simply visual studio has extended functionality and 'auto-coding-style' (it arranges the lines according to braces etc.)

[@adeepnair]

how do i do this with a text file with numbers in it?

[@TheSheniceJ]

+Adeep Nair ik its like a year u posted this but same thing i wanna know :(

[@TheAl2kas]

Hey, thanks for a useful tutorial, but I have a little problem. Program won't print last word. How do I fix it? :l

[@Pcatalin66]

+Aldis Petrauskas That is because the text is in that "char word[50]" and word[50] have only 50 slots. If you enter an text longer that 50 caracters (space included) than your program will cut the rest and stop at the 50 caracter. :D make sure that you give more than [50] ... maybe word[100] will help you .

[@RexGalilae]

+Aldis Petrauskas The reason is because he types *bucky>>word* before *cout

[@RexGalilae]

Lily Rathbun You first open the file and give it an alias (i.e. a placeholder) name, in this case, bucky. If you opened the file as , say "Lily", then you simply swap out all the "bucky"s from the code with "Lily"s. Pls. tell me if I misunderstood your question. I think I have misunderstood it.

[@RexGalilae]

Lily Rathbun If you're talking about the location of the file in the directory, then it's automatically created in the same folder as your program.

[@15sunny1]

+Mohammed Zaid Thank you!

[@muhammadmohaiminulislam7189]

Can i write or read a character in a file at a selected position?Like adding 'a' at 2nd line , third position at file? Or read from a selected position?

[@stephenreader5953]

Thank you!

[@dkblade27]

I thought when we open a file that we don't have, C++ will create it for us. So how come tunafeesh.txt didn't open??

[@sabrinazeb]

Thanku so much awesome tutorials.. :D

[@SuperFireEagle]

how would you code it to where it can automatically detect the input file name without hardcoding the name of the file into the program?

[@Lightscribe225]

Say I wanted to take a list of random numbers from a file, and find their sum and average. How do I go about doing that? Do you have a tutorial going over that somewhere?

[@yoloop93]

mine doesn't open as text file but opens with cmd.help!

[@insomeperson]

Why does it always ignore the last word?

[@GNSstudios]

you showed how to write a file but what if i wanted to write the file to a specific directory.

[@Milo_1105]

Or you can put main as a void and do not worry about returns.

[@netherar]

great tutorial! ty

[@dyrokudobane]

I see the program terminated once it reached the end-of-file, so the c++ part didn't print out. Probably wanna take the word from the back file then print it out right after within the while good loop ( omitting the bucky >> word line). Regardless, not bad.

[@NubPaws]

Or... He could have stored the file in a string variable using the cin.getLine(strVarName); I would assume that would be simpler.

[@stereojos86]

you save the txt doc in the same folder that the program? My program dont read the txt, go directly to exit(EXIT_FAILURE); I copy and paste your program.

[@durraiz_ahmad18]

Can you tell how can I skip/ignore line or row while reading a csv file and storing it in a 2d array?

[@shekhardk]

Well this code doesn't read and print the last word in the file. If the file has just one word then it won't print anything.

[@TheHeadmanmr]

What is this used for?? Would be much easier for my brain if I knew how this would be used in a real situation... !

[@zeen5163]

does "bucky >> word" get the word from the user and stores it in the file? or what does that actually do?

[@IvanRubinson]

I want to make my program read the first line and execute it (For example, if in the file it says Cout

[@pranoydutta5435]

instead of including the cstdlib to use exit, can we just return 124721; as this is in main

[@AndToeKnee1]

what if you want to copy codes from a website and paste it back like the ones to prove your not a computer ? lol

[@RaamAnkka]

wait guys only thing dont understand is that what is "word" used for... is that a variable he made up???

[@davidalyakobi6857]

Hey Bucky why did you use exit(EXIT_FAILURE) instead of exit(1) ?

[@Mrlpjo]

@TheResponsae. Is that really needed??? I think the file automatically closes once the execution is over?!

[@ivaka92]

while i was watching this tutorial i sat back in my chair, adjusted my glasses and said to myself "shit just got real"....

[@WikiPeoples]

how come it didnt read the entire line? It left out "C++!" .... mines doing the same thing