In which way structure differ from an array ? Describe with examples, the different ways of assigning values of structure members.

Answer:

Both the arrays and structures are classified as structured data types as they provide a mechanism that enable us to access and manipulate data in a relatively easy manner. But they differ in a number of ways.

The following are the differences between structures and arrays:

- Array elements are homogeneous. Structure elements are of different data type.

- Array allocates static memory and uses index / subscript for accessing elements of the array. Structures allocate dynamic memory and uses (.) operator for accessing the member of a structure.

- Array is a pointer to the first element of it. Structure is not a pointer

- Array element access takes less time in comparison with structures.

- An array is a derived data type. A structure is a programmer-defined data type

-  Any array behaves like a built-in data types. All we have to do is to declare an array variable and use it. But in the case of structure, first we have to design and declare a data structure before the variable of that type are declared and used.

Describe with examples, the different ways of assigning values of structure members.

We can access and assign values to the members of a structure in a number of ways. As mentioned earlier, the members themselves are not variables. They should be linked to the structure variables in order to make them meaningful members. For example, the word title, has no meaning whereas the phrase ‘title of book3’ has a meaning. The link between a member and a variable is established using the member operator ‘ . ’ which is also known as ‘dot operator’ or ‘period operator’.

For Example: 1

            book1.price

is the variable representing the price of book1 and can be treated like any other ordinary variable. Here is how we would assign values to the members of book1:

            strcpy(book1.title, “BASIC”);

            strcpy(book1.author, “Balagurusamy”);

            book1.pages = 250;

            book1.price = 120.50;

Example: 2

            book1.price

is the variable representing the price of book1 and can be treated like any other ordinary variable. Here is how we would assign values to the members of book1:

            strcpy(book1.title, “ANSi”);

            strcpy(book1.author, “Dennis M. Ritchie”);

            book1.pages = 600;

            book1.price = 300;