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Working with String Handling Functions in C

 C provides large set of string handling library function under string.h header. Few of them are discussed below. Strlen This function returns the length of the given string which is an integer value. Syntax strlen (name_of_array); The actual parameter for the function is the address of the first character of the array. Usage # include < stdio.h > # include < string.h > int   main () { char   name [] = " Abhilekh " ; printf ( " length is  %d " , strlen ( name )) ; return   0 ; } The output is: The  length  of the string is  8 Strcpy It should be noted that a string cannot be assigned to another string using a assignment operator(=). This is where we use this library function. It copies one string to another. Syntax strcpy (string1,string2); It copies the string from string2 to string1. Usage # include < stdio.h > # include < string.h > int   main () {   char   name [] = " Abhilekh " ;   char   copyName [ 8 ];   strcpy ( copyName , n

What is Structure and why do we need them in C

 In one of our previous post we dealt with Array .Here in this post we'll be dealing with structure which  I prefer to call 'The advanced version of arrays'. Structure Similar to an array, A structure is a collection, however of a dissimilar data types. Take an example of an office, Where the Manager wants to keep  the records of his/her employees.The record may include employees' name, address, department, pay scale , age and so on.So, why not create a variable with all those features in it. So when we want an entity with multiple features in it we can go with structures. First Glance of Structure struct   student {      int   rollNo , intake Year;      char   name [ 20 ], address [ 20 ]; }; Above is a structure student with some of the features of the student like:Roll number, intake year, their name and address. The keyword struct is used to define a structure. Structure definition always ends with a semicolon. The general form of Structure definition is struct   <

Arrays and static Memory allocation in C

In this post we will be talking about array, their usage and importance in C. Array Array in simple world is a collection/container of elements of  same type. Array of any type is possible but the elements in array cannot be of multiple types. We can have array of int type. But not a array with 5 element of int and other element of other types . Why Array? Imagine a problem where you want to input the marks of 10 student in a subject  from the user and display the marks in descending number. Our major problem above will be to store the number input by the user. Here we have two options : Either construct 10 variables for storing marks of 10 student .(A trash Idea) Or Construct a container (Array of integers in this case) which can store all the marks of student . First Glance of an Array As mentioned earlier array is a nothing else than a collection for us. int   marks [ 10 ]  =  { ' 1 ' , ' 2 ' , ' 3 ' , ' 4 ' , ' 5 ' }; This is what an array lo

What is Dynamic Memory Allocation in C

Under stdlib header C provides us 4 four special function which helps in allocating memory dynamically and freeing it. malloc() calloc() realloc() free() The first three function's are used in allocation of memory while the last one frees the allocated memory. The Malloc function Syntax malloc ( number_of_bytes ); The malloc function  allocates contiguous memory location for the required   number_of_bytes, returns a void pointer pointing to the base address of that allocated memory. A malloc returns a void pointer,why?because malloc does not know for what we allocated the memory ( malloc does not know whether we are allocating memory for ints , floats or chars ). Usage example int   * a = ( int * )  malloc (5 *sizeof ( int )); The (int*) is done for typecasting, it converts the void pointer returned by malloc function to a integer pointer (int*) . We are then assigning the returned(and type casted) pointer to a integer point a. So a is now pointing to the base address of allocated