peek

[shaharhada]

I saw in the documentation of the c++ the description of peek:

Instream::peek (member function)

Decalration:
Int peek()

Remarks:
Returns next char with extraction.
What does this function do? (in C++)
Can somebody explain me in other words the documentation of the instruction?

 

[USAFRet]

peek – Simple C++ Tutorials

Posts about peek written by aljensen

simplecplusplus.wordpress.com

"The peek() function looks into the input stream and tells us what the next character is without removing it from the input stream. Moreover, the peek() function can store the character in a designated memory locatio without actually removing it from the stream."


Given a stream of data coming IN, the 'peek' can look at the next character, without doing anything with it.
This can be used for a prediction of what to do next.

 

[shaharhada]

peek – Simple C++ Tutorials

Posts about peek written by aljensen

simplecplusplus.wordpress.com

"The peek() function looks into the input stream and tells us what the next character is without removing it from the input stream. Moreover, the peek() function can store the character in a designated memory locatio without actually removing it from the stream."


Given a stream of data coming IN, the 'peek' can look at the next character, without doing anything with it.
This can be used for a prediction of what to do next.

Can you explain the underlined text?

 

[USAFRet]

Can you explain the underlined text?

It can be used to determine End Of FIle (EOF), End of Line, or a potential fail.

 

[shaharhada]

It can be used to determine End Of FIle (EOF), End of Line, or a potential fail.

O.K. what is potential fail? ( for example...?)

 

[USAFRet]

O.K. what is potential fail? ( for example...?)

The device I'm trying to talk to is not online
Invalid input from something else (ex: expecting a number but getting a character)

 

[shaharhada]

The device I'm trying to talk to is not online
Invalid input from something else (ex: expecting a number but getting a character)

I still not understand. Do I get by peek function an error code message or number of error code? What am I get?

 

[Colif]

those are old commands...

I remember them from BASIC

PEEK and POKE - Wikipedia

en.wikipedia.org

Peek just shows you the results of your search, potential fail might just not return a result. That is just a guess.

 

[USAFRet]

I still not understand. Do I get by peek function an error code message or number of error code? What am I get?

This is getting reasonably deep into C++ programming.

This peek function is but one tiny part of a whole program or function.

 

[shaharhada]

those are old commands...

I remember them from BASIC

PEEK and POKE - Wikipedia

en.wikipedia.org

Peek just shows you the results of your search, potential fail might just not return a result. That is just a guess.

The are 2 commands in C: one is peek as in BASIC language and the second that I asked in C++ with the documentation that I give.

 

[shaharhada]

This is getting reasonably deep into C++ programming.

This peek function is but one tiny part of a whole program or function.

What is getting reasonably deep (in something)?
What is reasonably?

 

[USAFRet]

What is getting reasonably deep (in something)?
What is reasonably?

Means this is addressed in a programming class, not a simple Forum discussion.

 

[shaharhada]

Thanks,
Good day to the everyone in this forum.

 

[hotaru.hino]

Normally when you read something from a stream (which is data that's coming in from some source), you want to both read what's in the buffer (where the data is stored) and take it out of the buffer. The reason for taking out of the buffer is so you can have room for more data in case the data stream sends more stuff. As far as the program's concerned, a stream is a stream, it can be a file stream (where there's no real time constraint) or something from the internet (where you might lose the data if you don't get it out in time).

One reason to use a peek is to look ahead in the stream's buffer to determine if you need to do anything more and you don't want to copy the data somewhere. Backtracking from a stream is often not possible and having a copy of data you don't need may be wasteful.

 

[shaharhada]

Normally when you read something from a stream (which is data that's coming in from some source), you want to both read what's in the buffer (where the data is stored) and take it out of the buffer. The reason for taking out of the buffer is so you can have room for more data in case the data stream sends more stuff. As far as the program's concerned, a stream is a stream, it can be a file stream (where there's no real time constraint) or something from the internet (where you might lose the data if you don't get it out in time).

One reason to use a peek is to look ahead in the stream's buffer to determine if you need to do anything more and you don't want to copy the data somewhere. Backtracking from a stream is often not possible and having a copy of data you don't need may be wasteful.

What is backtracking?

Backtracking from a stream is often not possible and having a copy of data you don't need may be wasteful.

 

[hotaru.hino]

What is backtracking?

It means going back to what you saw before.