C ARRAYS


The C language provides a capability that enables the user to define a set of ordered data items known as an array.
What is an Array in C Language?

An array in C Programing Language can be defined as number of memory locations, each of which can store the same data type and which can be references through the same variable name.
An array is a collective name given to a group of similar quantities. These similar quantities could be percentage marks of 100 students, number of chairs in home, or salaries of 300 employees or ages of 25 students. Thus an array is a collection of similar elements. These similar elements could be all integers or all floats or all characters etc. Usually, the array of characters is called a “string”, where as an array of integers or floats is called simply an array. All elements of any given array must be of the same type i.e we can’t have an array of 10 numbers, of which 5 are ints and 5 are floats.
Declaration of an Array

Arrays must be declared before they can be used in the program. Standard array declaration is as
type variable_name[lengthofarray];

Here type specifies the variable type of the element which is going to be stored in the array. In C programmin language we can declare the array of any basic standard type which C language supports. For example

double height[10];
float width[20];
int min[9];
char name[20];


In C Language, arrays starts at position 0. The elements of the array occupy adjacent locations in memory. C Language treats the name of the array as if it were a pointer to the first element This is important in understanding how to do arithmetic with arrays. Any item in the array can be accessed through its index, and it can be accesed any where from with in the program. So

m=height[0];
variable m will have the value of first item of array height.

The declaration int values[10]; would reserve enough space for an array called values that could hold up to 10 integers. Refer to the below given picture to conceptualize the reserved storage space.

values[0]          CONTINOUS MEMORY LOCATIONS
values[1]         
values[2]         
values[3]         
values[4]         
values[5]         
values[6]         
values[7]         
values[8]         
values[9]         

The program below will declare an array of five integers and print all the elements of the array.
int myArray[5] = {1,2,3,4,5};
/* To print all the elements of the array
for (int i=0;i<5;i++){
   printf("%d", myArray[i]);
}

Initializing Arrays:

Initializing of array is very simple in c programming. The initializing values are enclosed within the curly braces in the declaration and placed following an equal sign after the array name. Here is an example which declares and initializes an array of five elements of type int. Array can also be initialized after declaration. Look at the following C code which demonstrate the declaration and initialization of an array.

int myArray[5] = {1, 2, 3, 4, 5}; //declare and initialize the array in one statement
int studentAge[4];
studentAge[0]=14;
studentAge[1]=13;
studentAge[2]=15;
studentAge[3]=16;

To summarize, arrays provides a simple mechanism where more than one elements of same type are to be used. We can maintain, manipulate and store multiple elements of same type in one array variable and access them through index.