You should try to pick sensible (i.e. meaningful) names for your variables. Names like x, or rude words, may be tolerated by the compiler but I find them rather silly.

The name of the variable should reflect the use it is being put to. The only exception to this is that I find that when I create a simple variable for counting I tend to give it the name i. This is because I am very old, and the name i used to have significance on older computers. It is also quick and easy to type and so I make no apology for this technique and commend it to you.

As a rule of thumb your variables should have names no longer than 8 characters or so, but the name should summarize what you are using it for.

Some people put the type of the variable in the name, you can do this if you think it would be sensible.

/*  Simple Variable  */
void main ( void )
{
  /* create an integer variable  */
  int count ;
}