Chapter 7
Arrays
An array is a collection of simillar datatypes.
one variable = capable of storing multiple values
syntax
The syntax of declaring an array looks like this
char hytek[90]; character array
float hytek[90]; float array
int hytek[90]; integer array
The values can now be assigned to hytek array like this
hytek[0] = 34;
hytek[1] = 78;
Note : It is very important to note that the array index starts with 0
Accessing elements
Elements of an array can be accessed using
scanf("%d",&hytek[0]); input first value
printf("%d",&hytek[0]); output first value
Initialization of an Array
There are many other ways in which an arraycan be initialized
int hytek[4] = {3,5,6,7}
float hytek[3] = {3.3,4.4,5.6}
Arrays can be initialized while declaration
Arrays in Memory
int arr [3] = {1,2,3} //1 integer = 4 bytes
This will reserve 4*3 = 12 bytes in memory 4 bytes for each integer
Pointer Arithmetic
A pointer can be incremented to point to the next memory location of that type
Consider this example
int i = 44;
int *q = &i;q=87567
q++; now q=87571 #address 87567
same for char or float but in char address will incremented to 1 or in float also same as integer
Following operation can be performed on a pointers :
- Addition of a number to a pointer
- subtraction of a number from a pointer
- subtraction of one pointer from another
- comparison of two pointer variables
Accessing Arrays using pointers
Consider this array /// if ptr points to index 0,ptr++ will point to index 1& so on…
This way we can have an integer pointer pointing to first element of the array like this
int*ptr=&arr[0]; or simply arr
ptr++
*ptr will have 4 as its value
passing arrays to functions
Arrays can be passed to the function like this
print Array (arr,n); //function call
void print Array(int*i,int n); //function prototype
void print Array (int i [ ],int n);
multidimensional Arrays
an array can be of 2 dimension /3 dimension /n dimensionA
2 dimensional array can be defined as
int arr [3][2] = {{1.3}
{ 7,6}
{9,8}};
we can access the elements of this array as arr[0][0],arr[0][1],and so on…
2d arrays in memory
a 2d array same as 1d array is stored in contiguous memory blocks like this
HYTEK 