Training, Open Source Programming Languages

This is page http://www.wellho.net/mouth/3807_Rea ... in-C-.html

Our email: info@wellho.net • Phone: 01144 1225 708225

 
For 2021 - online Python 3 training - see ((here)).

Our plans were to retire in summer 2020 and see the world, but Coronavirus has lead us into a lot of lockdown programming in Python 3 and PHP 7.
We can now offer tailored online training - small groups, real tutors - works really well for groups of 4 to 14 delegates. Anywhere in the world; course language English.

Please ask about private 'maintenance' training for Python 2, Tcl, Perl, PHP, Lua, etc.
Reading (and writing) files in C++

"But how do I read data from a file ....?". Question on a C++ course on which we had concentrates, thus far, on object orientation.

In summary:
1. Include the fstream header file
2. Create an object of type ifstream using the constructor, and passing in the file name
3. Read lines from the ifstream object using the getlines method
4. Check for end of file using the eof method

In code:
  #include <fstream>
  ifstream infile("requests.xyz");
  infile.getline(myline,256);
  if (infile.eof()) break;

with the latter two statements in a loop. Complete source [here].




Writing a file? use an ofstream!

I've added a full example of input and output [here] on our web site.

In the example, a file (named on the command line) is read in line by line, and is combed - i.e. a sample of one line in every 10 (or 15, or 20, or any other number given on the command line) is output - either to the screen, or to an output file if one is named on the command line.

The program includes extensive (but NOT complete) data validation, checking whether the files open correctly, and whether the correct number of parameters were given on the command line.




We offer a range of C and C++ courses - for newcomers to programming, as well as to delegates with prior programming experience. See [here] for details.

(written 2012-07-18, updated 2012-08-11)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
C235 - C and C based languages - I/O in C++
  [1478] Some new C programming examples - files, structs, unions etc - (2007-12-19)
  [1675] Comparing Objects in C++ - (2008-06-13)
  [3124] C++ - putting the language elements together into a program - (2011-01-08)
  [3252] C++ - unknown array size, unknown object type. Help! - (2011-04-17)
  [3390] Printing objects in C++ - (2011-08-13)
  [3810] Reading files, and using factories to create vectors of objects from the data in C++ - (2012-07-21)
  [4562] Left shift operator on an output stream object - C++ - (2015-10-30)
  [4563] Formatting and outputting your own classes in C++ - (2015-10-30)


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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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