Structure of program

/* This program prints Hello World on screen */

-----------------------------
#include
Void main()
{
  printf(''Hello World '');
}
-----------------------------

1 . /* This program ... */

The symbols/* and*/ used for comment. This Comments are ignored by the compiler, and are used to provide useful information about program to humans who use it.

2. #include

This is a preprocessor command which tells compiler to include stdio.h file.

3. main()

C programs consist of one or more functions. There must be one and only one function called main. The brackets following the word main indicate that it is a function and not a variable.

4. { }

braces surround the body of the function, which may have one or more instructions/statements.

5. printf()

it is a library function that is used to print data on the user screen.

6. ''Hello World '' is a string that will be displayed on user screen 
is the newline character.
; a semicolon ends a statement.

7. return 0; return the value zero to the Operating system.


C is case sensitive language, so the names of the functions must be typed in lower case as above.

we can use white spaces, tabs & new line characters to make our code easy to read. 

Example of Structure in C

#include 
/* Created a structure here. The name of the structure is
 * StudentData.
 */
struct StudentData{
    char *stu_name;
    int stu_id;
    int stu_age;
};
int main()
{
     /* student is the variable of structure StudentData*/
     struct StudentData student;

     /*Assigning the values of each struct member here*/
     student.stu_name = "Steve";
     student.stu_id = 1234;
     student.stu_age = 30;

     /* Displaying the values of struct members */
     printf("Student Name is: %s", student.stu_name);
     printf("
Student Id is: %d", student.stu_id);
     printf("
Student Age is: %d", student.stu_age);
     return 0;
}



Output:


Student Name is: Steve
Student Id is: 1234
Student Age is: 30