wiki:ResumedC

Version 3 (modified by Thanatermesis, 15 years ago) ( diff )

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Note: This is not pretended to be a Howto, also not really public, it is just a page that i have used to take some notes of a interesting book of C that im reading, you are allowed to edit and correct this document if you see anything wrong, also order it a bit or made it better, but this not pretends to be a big document so try to maintain it compact. Thanks


Comments

The comments are very important for yourself basically, you need to comment all your functions and declarations, and specially you need to comment your variables in order to know *what* exactly they are, and also for know possible special things of these variables

It is recommended to learn how works doxygen (5 minutes reading a howto in google, it is very basic) so that you can know special techniques to comment your source code that then you can build documentation of your API/source directly from these comments

The special things that you need to have in mind when you code is: clarity of code, simplicity, and summary

Basic Things

To declare a string in a variable, you need to use strcpy, so

   name = "Me";   /* Illegal */
   strcpy (name, "Me");    /* Legal */

When you assign a single character you need to enclose it in single-quotes ', if you want to assign a string (with the end-of-string (NULL) char included), you need to use double-quotes ".

A good way to remove the newline value from variables (when you use a input-line entry system) is by simply set the end-of-string (NULL) value to the newline place, like:

   fgets(first, sizeof(first), stdin);
   first[strlen(first)-1] = '\0';

Remember that a string contains first a newline (if the input has included a newline) and all the strings finishes by the '\0' (NULL) character

Arrays

A two dimensional matrix looks like:

   mtrx_var[2][4];

Notice that this form is illegal:

   mtrx_var[2,4];

This is also valid:

   int mtrx_var[2][4] = 
       {
          {1, 2, 3, 4},
          {10, 20, 30, 40}
       };

Variables

signed: means with sign, so, values negative and positive, for example if the char variable has a limit of 255 values, using the sign mode we can use from -128 (negative) to 127 (positive), and using unsigned we can use from 0 to 255

The constant variables are constants, so they can't change, by convention they are in upper-case

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