Structures

• A Structure is a container, it can hold a bunch of variables.
  • These variables can be of any type.
• It is a user defined data type used to group related data (i.e. variables)
• Each variable in a structure can have similar or different data type than other variables of that structure.
• Structures-Basic data types:
  • char, int ,float, long, double etc.
    • char is used to store a character in memory for later access.
    • int is used to store an integer in memory for later access.
    • Similarly other basic types are used to store their relevant data for later access.
  • User Defined Data Type:
    • We want to store the record of a student or of employees of an organization or community centres in a city
    • No basic data type provide us the facility to store these records because all these require a combination of more than one basic data types
    • g. Student will have name, class, reg. No. etc…
    • Example – Student Record;
    • Student Record:
      • Name a string
      • Roll No. an integer
      • Class             a string
      • CGPA             a float
    • Structure Members;
      • Each variable in a structure is called member.
      • Each member has a name, a type and a value.
      • Names follow the rules for variable names.
      • Types can be any basic data type.
    • Defining a Structure;
      • By defining a structure you create a new data type.
      • Once a struct is defined, you can create variables of the new type.
      • Just like you created the variables of basic data types

e.g. int x;

StudentRecord stu;

• If a variable is declared, appropriate memory becomes reserved for that variable

e.g. declaring an integer reserves 4 bytes in memory

• While declaring a variable (instance) of a structure reserves the sum of memory requirements of all of its members.
• i.e Variable of StudentRecord structure will reserve 38 bytes in memory