A primary key is a column which uniquely identifies the records in a table. In a broad sense, a primary key is the mixture of a unique key and an index: A column with a primary key is indexed to deliver a faster query, and doesn't allow duplicate values to ensure specific data. Most programmers recommend all tables having a primary key (and only one) to enhance the speed of queries and overall database performance. An example of a primary key may be found in a table named "departments," which might have a column named "department_number" that uniquely identifies each department in the table with a number.

A foreign key is a column (the child column ) in a table which has a corresponding relationship and a dependency on another column (the parent column ) that is usually in a different table. Parent columns can have multiple child columns, but a child column can only have one parent column. The child column is the column with the foreign key; the parent column does not have the foreign key "set" on it, but most databases require the parent column to be indexed. Foreign keys are made to link data across multiple tables. A child column cannot have a record that its parent column does not have. Say a table named "employees" has 20 employees (rows) in it. There are 4 departments in the "departments" table. All 20 employees must belong to a department, so a column in the "employees" table named "department" would point to the primary key in the "departments" table using a foreign key. Now all employees must belong to a department as specified by the "departments" table. If a department isn't specified in the "departments" table, the employee cannot be assigned to it.

A candidate key would be any key which could be used as the primary key, which means that the combination of the columns, or just the single column would create a unique key. You would then need to determine which of these candidate keys would work best as your primary key.

A visual metaphor, also called a pictorial metaphor, is a metaphor in which something (the metaphor's "target") that is presented visually is compared to something that belongs to another category (the metaphor's "source") of things than the first, also presented visually. As in verbal metaphors (such as "football is war" or "the world is a stage"), at least one feature or association is "mapped" from the source to the target. Often, a whole set of (interrelated) features is mapped from source to target. Visual/pictorial metaphors are used often in advertising, but also in political cartoons and films. Many examples of visual/pictorial metaphor, as well as discussions of them, are discussed in my book Pictorial Metaphor in Advertising(Routledge 1996), which also contains references to the work of other authors who discuss metaphor in images and film, for instance the perception psychologist John Kennedy, the film scholar Trevor Whittock, and the film philosopher Noel Carroll.

Nowadays, metaphors straddling two or more modalities (language, visuals, sound, gesture ...) are beginning to receive serious scholarly attention. Metaphors in which the target and the source are in different modalities are called "multimodal metaphors." An example of the latter is an advertisement for a photo camera (target, in the visual modality) with underneath the text "supermodel" (source, in the verbal modality). For more information, see my online course *A Course in Pictorial and Multimodal Metaphor.*

In September 2009 the volume Multimodal Metaphor (Mouton de Gruyter) appeared, which I co-edited with Eduardo Urios-Aparisi. More information on this topic can be found on the Adventures in Multimodality (AIM) blog [Contribution by Charles Forceville.]

#include

#include

main()

{

int n,i,c,a=0,b=1;

printf("Enter Fibonacci series of nth term : ");

scanf("%d",&n);

printf("%d %d ",a,b);

for(i=0;i<=(n-3);i++)

{

c=a+b;

a=b;

b=c;

printf("%d ",c);

}

getch();

}

Output :

Enter Fibonacci series of nth term : 7

0 1 1 2 3 5 8

#include < p18f452.h >

//these memory locations hold the Fibonacci series

unsigned char fib0; //lowest number

//(oldest when going up, newest when reversing down)

unsigned int fib1; //middle number

unsigned float fib2; //highest number

unsigned double fibtemp; //temporary location for newest number

main ()

{

counter 3; //have preloaded the first three numbers, so start at 3

fib0 0;

fib1 1;

fib2 1;

loop: do

{

float test0;

fibtemp fib1 + fib2;

counter counter + 1;

//now shuffle numbers held, discarding the oldest

fib0 fib1; //first move middle number, to overwrite oldest

fib1 fib2;

fib2 fibtemp;

}

while (counter<12):

//when reversing down, we will subtract fib0 from fib1 to form new fib0

do

{

fibtemp fib1 - fib0; //latest number now placed in fibtemp

counter counter - 1;

//now shuffle numbers held, discarding the oldest

fib2 fib1; //first move middle number, to overwrite oldest

fib1 fib0;

fib0 = fibtemp;

}

while (fib0>0);

go to loop

return 10;

}

tell me problem

There is no keyword for it. You can use a variable of 1 class in another only id the other class is derived from the 1st class.

Although you can use the variable of an object of a class in another class using object.variable