What is file template?

This is a condition which is passed to the operating system for matching or searching. For example, entering *.TXT will list all files which have the extension .TXT. There are two legal wild-cards: the question mark? Which stands for a single non-specified character, and the asterisk *, which stands for more than one, for example, *.TXT, LETTER?.DOC. The template *.* includes all files.

What are Constants in C++?

Constants are expressions with a fixed value or the value that cannot be changes.

Literals

Literals are used to express particular values within the source code of a program. We have previously used these previously to provide concrete values to variables or to express messages we wanted our programs to print out.

F example, when we wrote:

int x=5;

the 5 in this piece of code was a literal constant.

The Literal constants can be divided in Integer Numerals, Floating-Point Numerals, Characters, Strings and Boolean Values.

Microprogramming

Microprogramming is the concept of microprogramming was developed by Maurice Wilkes in 1951, by means of diode matrices for the memory element. A microprogram consists of a sequence of micro-instructions in a microprogramming.

Microprogramming (i.e. writing microcode) is a way that can be employed to execute machine instructions in a CPU fairly easily, often using less hardware than with other methods. It is a set of very full and rudimentary lowest-level routines which controls and sequences the actions needed to carry out (perform) particular instructions, at times also to decode (interpret) them. A machine instruction implemented by a series of microinstructions is therefore loosely similar to how an interpreter implements a high-level language statement by means of a series of machine instructions.

Pointers and function in C programming language

The pointer is very much used in a function declaration. Sometimes only with a pointer a complex function can be simply represented and success. The usage of the pointers in a function definition possibly will be categorized into two groups.
1. Call by reference
2. Call by value.

Call by value

We have seen that a function is called there will be a link established between the formal and actual parameters. A temporary storage space is created where the value of actual parameters is stored. The formal parameters picks up its value from storage space area the method of data transfer relating actual and formal parameters allows the actual parameters mechanism of data transfer is referred as call by value. The corresponding formal parameter represents a local variable in the called function. The current value of matching actual parameter becomes the initial value of formal parameter. The value of formal parameter can be changed in the body of the actual parameter. The value of formal parameter can be changed in the body of the subprogram by task or input statements. This will not change the value of actual parameters.

/* Include<>
void main()
{
int x,y;
x=20;
y=30;
printf(“\n Value of a and b before function call =%d %d”,a,b);
fncn(x,y);
printf(“\n Value of a and b after function call =%d %d”,a,b);
}

fncn(p,q)
int p,q;
{
p=p+p;
q=q+q;
}

Call by Reference

The process of calling a function by using pointers to pass the address of the variable is known as call by reference. The function which is called by reference can change the values of the variable used in the call.

/* example of call by reference*?

/* Include<>
void main()
{
int x,y;
x=20;
y=30;
printf(“\n Value of a and b before function call =%d %d”,a,b);
fncn(&x,&y);
printf(“\n Value of a and b after function call =%d %d”,a,b);
}

fncn(p,q)
int p,q;
{
*p=*p+*p;
*q=*q+*q;
}

What is graphical user interface?

A graphical user interface (GUI) is a kind of user interface which lets people to interrelate with electronic devices like computers, hand-held devices (Portable Media Players, MP3 Players, Gaming devices), household appliances and office equipment. A GUI gives graphical icons, and visual indicators as opposite to text-based interfaces, typed command labels or text navigation to entirely symbolize the information and actions available to a user. The actions are generally performed through direct manipulation of the graphical elements.

The word GUI is historically restricted to the scope of two-dimensional display screens with display resolutions competent of describing generic information, in the tradition of the computer science research at Palo Alto Research Center (PARC) (previously Xerox PARC and still a subsidiary of Xerox).The word GUI earlier may have been appropriate to other high-resolution types of interfaces that are non-generic, like videogames, or not restricted to flat screens, for example volumetric displays.