Declarations in C programming

A declaration associates a group of variables with a specific data type. All variables must be declared before they can appear in executable statements. A declaration consists of a data type, followed by one or more variable names, ending with a semicolon. Each array variable must be followed by a pair of square brackets, containing a positive integer which specifies the size (i.e. the number of elements) of the array.

A C program contains the following type declarations:

int a, b, c ;

float root1, root2 ;

char flag, text [80],

Thus, a, b and c are declared to be integer variables, root1 and root 2 are floating variables, flag is a char-type variable and text is an 80-element, char-type array. Square brackets enclosing the size specification for text.

These declarations could also have been written as follows:

int a ;

int b ;

int c ;

float root1 ;

float root2 ;

char flag ;

char text [80] ;

# A C program contains the following type declarations:

short int a, b, c ;

long int r, s, t ;

int p, q ;

Also written as

short a, b, c ;

long r, s, t ;

int p, q ;

short and short int are equivalent, as are long and long int.

# A C program contains the following type declarations

float c1, c2, c3 ;

double root1, root2 ;

also written as

long float root1, root2 ;

# A C program contains the following type declarations.

int c = 12 ;

char star = ‘*’ ;

float sum = 0. ;

double factor = 0.21023e-6

Thus, c is an integer variable whose initial value is 12, star is a char type variable initially assigned the character ‘*’, sum is a floating point variable whose initial value is 0. , and factor is double precision variable whose initial value is 0.21023 × 106.

# A C program contains the following type declarations.

char text [ ] = “California” ;

This declaration will cause text to be an 11-element character array. The first 10 elements will represent the 10 characters within the word California, and the 11th element will represent the null character (\0) which automatically added at the end of the string.

Te declaration could also have been written

char text [11] = “California” ;

Where size of the array is explicitly specified. In such situations, it is important, however, that the size be specified correctly. If the size is too small, eg. ,

char text [10] = “California” ;

The character at the end of the string (in this case, the null character) will be lost. If the size is too large e.g.,

char text [20] = “California” ;

The extra array elements may be assigned zeros, or they may be filled with meaningless characters.

c a l i f o r n i a \0

The array is another kind of variable that is used extensively in C. An array is an identifier that refers to collection of data items that have the same name. The data items must all be of the same type (e.g. all integers, all characters). The individual data items are represented by their corresponding array element (i.e. the first data item is represented by the first array element, etc). The individual array elements distinguished from one another by the value that is assigned to a subscript.

Subscript: 0 1 2 3 4 5 6 7 8 9 10

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...

CPU (Central Processing Unit)

PGA reffered as pin grid array in which pins of CPU are lined up in a straight format. SPGA referred as staggered pin grid array. in which pins of CPU are arranged staggered format. LGA reffered to as Land Grid Array in which pins are available within inside the socket but not in the CPU in other words in line grid array, in CPU ther are no pinsbut insteadpins areattached with in a socket which contact with with the CPU. for e.g. LGA775 socket(no pins on cpu) has better cooling system. better contact and better locking(climbing). LGA1155: Letest generation I socket, also reffered as sandy bridge, Turbo boost overclocking. More resent than LGA 1156 socket. LGA1156: ability to north bridge Doul channel DDR3 optional integreted graphics PCI express LGA1366: hi end core i series socket integreted tiple channal memmory controller external control bridge(HUB) Upgrading CPU: need to check its core suppert check multiprocessor supports or not check on the ...

Recursive Function in C programming

If a statement within the body of a function calls the same function, the function is called recursive function. Actually, recursion is a process by which a function calls itself repeatedly until some specified condition has been satisfied. This process is used for repetitive computations in which each action is stated in term of previous result. Many iterative or repetitive problems can be written in this form. To solve a problem using recursive method, two conditions must be satisfied. They are: 1) Problem could be written or defined in term of its previous result. 2) Problem statement must include a stopping condition. /* An example of recursive function to calculate factorial of a number.*/ #include<stdio.h> #include<conio.h...

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