Operators in C programming : Special Operators

C supports some special operators such as comma operator, size of operator, pointer operator (* and &) and member selection operators. (.and →)

Comma Operator:

The comma operator can be used to link the related expression together. Comma linked lists of expression are evaluated left to right and the value of right-most expression is the value of combined expression. For example, value = (x = 10, y = 5, x + y),

Here, 10 is assigned to x and 5 is assigned to y and so expression x+y is evaluated as (10+5) i.e. 15.

Size of Operator:

The size of operator is used with an operand to return the number of bytes it occupies. It is a compile time operand. The operand may be a variable, a constant or a data type qualifier. The associativity of size of right to left. For example Suppose that i is an integer variable, x is a floating-point variable, d is double-precision variable and c is character type variable.

The statements:

printf (“integer : %d \n”, size of i) ;

printf (“float : %d \n”, size of x) ;

printf (“double : %d \n”, size of d) ;

printf (“character : %d \n”, size of c) ;

Unary expression Equivalent expression

++ variable or (variable ++) variable = variable +1

-- variable or (variable _ _) variable = variable -1

The investment or decrement operators can each be utilized two different ways, depending on whether the operator is written before or after. If the operator is written before the operand then it is called as prefix unary operator. If the operator is written after the operand, then it is called as postfix unary operator. When prefix is used, the operand will be altered in value before it is utilized for its intended purpose within the program. Similarly, when postfix is used, the operand will be altered in value after it is utilized. A C program includes an integer variable i whose initial value is 1. Suppose the program includes the following three printf statements.

printf (“i = %d\n”, i) ;

printf (“i = %d\n”, ++i) ;

printf (“i = %d\n”, i) ;

These printf statements will generate the following three lines of output:

i = 1

i = 2

Again, suppose printf (“i = %d\n”, i) ;

printf (“i = %d\n”, i++) ;

printf (“i = %d\n”, i) ;

These statements will generate the following three lines of output:

i = 1

i = 2

The precedence of unary increment or decrement is same and associativity is right to left.

Passing arrays to functions in C programming

Like any other variables, we can also pass entire array to a function. An array name can be named as an argument for the prototype declaration and in function header. When we call the function no need to subscript or square brackets. When we pass array that pass as a call by reference because the array name is address for that array. /* Program to illustrate passing array to function */ #include<stdio.h> void display(int) ; /* function prototype */ main( ) { int num[5] = {100, 20, 40, 15, 33, i ; clrscr( ) ; printf (“\n The content of array is \n”) ; for (i=0; i<5; i++) display (num[i]) ; /*Pass array element fo fun */ getch{ } ; } void display(int n) { printf (“\t%d”, n ) ; } Output: The content of array is 100 20 40 15 3 /* Program to read 10 numbers from keyboard to store these num into array and then c...

Explanation of Graphics in C programming

The header file graphics.h should be included to use graphics related built in functions. Again, the variable gDriver is an integer variable that specifies graphics driver to be used. Device drivers are small programs which talk directly to the hardware. Graphics drivers are a subset of device drivers and are applicable only in the graphics mode. The initialization of this variable to DETECT is to set another variable gMode to the highest resolution available for the detected driver. The value of this variable gDriver may be another than DETECT (e.g. 1 for CGA, 9 for VGA.). The variable gMode is an integer that specifies initial graphics mode. The built in function initgraph() is for graphics initialization. The syntax for this is as initgraph(&graphics_driver, &graphics_mode, path_to_driver); path_to_driver specifies the directory path where initgraph() looks for graphics drivers ( .BGI files). Thi...

BIOS

BIOS stands for Basic Input Output System. It is is kind of OS pre- attached in the system Design to detect every I/O devices It holds basic drivers -checks all I/O devices -Loads main OS -Responsible for starting System switched on manufactured by AMI,Phonix,award,Baiostar POST error test, boots trap load, BIOS is unintrusive system. CMOS and BIOS are two different components of the motherboard. CMOS work as storage if BIOS. A basic software program containing all BIOS is permanently stored in the ROM. every essencial holds program Tresh passing without knowinig is called intrusive.

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