Programming Blog

Every programs we were doing before were using Memory for storage and all those memory would wipe out once the program is terminated.But sometime the case is different,what if we need all those data again,We need to re-enter all those bulky data again,which will again be wiped out once the program is terminated. So we need to store the data in such a place such that it can be retrieved and displayed again and again.This is why we need files.The place about which we previously talked is the file on the disk.So we need File Handling to work with files. Let us see how a file can be handled. Various Operations in Files Creating a File Opening a File Reading from a File Writing to a File Closing a File File Opening Modes in C Before performing any operations in files,we must create/open the file . Here are the various File opening modes in C. "r" : It searches the file.If the file opens up successfully,the function fopen() loads the file from disk to memory and sets a pointer

 Variable declaration is not complete until we mention its storage class( there are some default conditions as well). Yeah you got it right ,Variables not only have data types they have storage class too. Why storage class? They tell us about The scope of the variable. Life time of the variable. Initial value of the the variable, if left unassigned. We have four storage class in C Automatic storage class External storage class Static storage class Register storage class Let us look at them one by one. Automatic Storage Class Scope : Local to the block where it is defined. Life Time : Until the control remains in the block. Initial value : A garbage value, one cannot predict. We use the keyword auto to declare a variable of automatic storage class. Demonstration of  Automatic storage class # include < stdio.h > void   myFunc (); int   main () {     auto  int   x   =   5 ;      printf ( " %d " , x ) ;      myFunc () ;      return   0 ; } void   myFunc () { int x;  

 In the previous post we discussed about  string handling functions in C . In this post we'll be defining our own version for those function. Let's see how. xstrlen As the name suggests xstrlen will be function performing same functions as strlen function which returns the length of the string. # include < stdio.h > int   xstrlen ( char   * ); int   main () { char   name [] = " Abhilekh " ; printf ( " length is  %d " , xstrlen ( name )) ; return   0 ; } int   xstrlen ( char   * a) {      int   length   =   0 ;      while ( * a != ' \0 ' )     {        length ++ ;       a ++ ;     }      return   length ; } Look at the function prototype. int   xstrlen ( char   * ); It is very clear that the function is expecting a character pointer as a parameter and the function will be returning a integer value. Let us now see how we are calling the function, xstrlen ( name ) We are passing the name_of_array as a parameter. It should be noted that the name of