ARRAY IN C++
C++ provides a data structure, the array, which stores a fixed-size sequential collection of elements of the same type. An array is used to store a collection of data, but it is often more useful to think of an array as a collection of variables of the same type.
Instead of declaring individual variables, such as number0, number1, ..., and number99, you declare one array variable such as numbers and use numbers[0], numbers[1], and ..., numbers[99] to represent individual variables. A specific element in an array is accessed by an index.
All arrays consist of contiguous memory locations. The lowest address corresponds to the first element and the highest address to the last element.
Declaring Arrays:
To declare an array in C++, the programmer specifies the type of the elements and the number of elements required by an array as follows:
type arrayName [ arraySize ];
This is called a single-dimension array. The arraySize must be an integer constant greater than zero and type can be any valid C++ data type. For example, to declare a 10-element array called balance of type double, use this statement:
double balance[10];
Initializing Arrays:
You can initialize C++ array elements either one by one or using a single statement as follows:
double balance[5] = {1000.0, 2.0, 3.4, 17.0, 50.0};
The number of values between braces { } can not be larger than the number of elements that we declare for the array between square brackets [ ]. Following is an example to assign a single element of the array:
If you omit the size of the array, an array just big enough to hold the initialization is created. Therefore, if you write:
double balance[] = {1000.0, 2.0, 3.4, 17.0, 50.0};
You will create exactly the same array as you did in the previous example.
balance[4] = 50.0;
The above statement assigns element number 5th in the array a value of 50.0. Array with 4th index will be 5th, i.e., last element because all arrays have 0 as the index of their first element which is also called base index. Following is the pictorial representaion of the same array we discussed above:
Accessing Array Elements:
An element is accessed by indexing the array name. This is done by placing the index of the element within square brackets after the name of the array. For example:
double salary = balance[9];
The above statement will take 10th element from the array and assign the value to salary variable. Following is an example, which will use all the above-mentioned three concepts viz. declaration, assignment and accessing arrays:
#include <iostream> using namespace std; #include <iomanip> using std::setw; int main () { int n[ 10 ]; // n is an array of 10 integers // initialize elements of array n to 0 for ( int i = 0; i < 10; i++ ) { n[ i ] = i + 100; // set element at location i to i + 100 } cout << "Element" << setw( 13 ) << "Value" << endl; // output each array element's value for ( int j = 0; j < 10; j++ ) { cout << setw( 7 )<< j << setw( 13 ) << n[ j ] << endl; } return 0; }
This program makes use of setw() function to format the output. When the above code is compiled and executed, it produces the following result:
Element Value 0 100 1 101 2 102 3 103 4 104 5 105 6 106 7 107 8 108 9 109
C++ Arrays in Detail:
Arrays are important to C++ and should need lots of more detail. There are following few important concepts, which should be clear to a C++ programmer:
| Concept | Description |
|---|---|
| C++ supports multidimensional arrays. The simplest form of the multidimensional array is the two-dimensional array. | |
| You can generate a pointer to the first element of an array by simply specifying the array name, without any index. | |
| You can pass to the function a pointer to an array by specifying the array's name without an index. | |
| C++ allows a function to return an array. |
//PROGRAM TO DELETE AN ELEMENT FROM AN ARRAY
#include<iostream.h>
#include<conio.h>
main()
{
int a[10];
int n,loc;
cout<<"enter the size of an array:-";
cin>>n;
cout<<"\nenter the elements:-";
for(int i=0;i<n;i++) //inserting element in an array
{
cin>>a[i];
}
cout<<"\nenter the postion of the element you want to delete:-";
cin>>loc;
if(loc >= n+1 ) //checking the validity of an location
cout<<"\nDeletion not possible.\n";
else
{
for(int i=loc-1;i<=n-1;i++)
{
a[i]=a[i+1]; //shifiting of an element in left
}
}
cout<<"\narray after deleting element is:-";
for(int i=0;i<n-1;i++)
{
cout<<a[i]<<endl; //displaying an array
}
getch();
}
//PROGRAM TO INSERT AN ELEMENT IN THE ARRAY
#include<iostream.h>
#include<conio.h>
main()
{
int a[10];
int n,item,loc;
cout<<"enter the size of an array:-";
cin>>n;
cout<<"\nenter the elements:-";
for(int i=0;i<n;i++) //entering elements in an array
{
cin>>a[i];
}
cout<<"\nenter the element you want to insert:-";
cin>>item;
cout<<"\nenter the location:-";
cin>>loc;
for(int i=n-1;i>=loc-1;i--)
{
a[i+1]=a[i]; //shifting the element by one index value
}
a[loc-1]=item; //copying the value at location
cout<<"\narray after inserting element is:-";
for(int i=0;i<n+1;i++)
{
cout<<a[i]<<endl; //display of an array
}
getch();
}
SEARCH UN ARRAY
#include<iostream.h>
#include<conio.h>
main(){
int a[100],i,n,wanted,count=0;
cout<<"Enter the size of an array:";
cin>>n;
cout<<"Enter the elements of the array: ";
for(i=0;i<n;i++)
{
cin>>a[i];
}
cout<<"Enter the number to be search: ";
cin>>wanted;
for(i=0;i<=n;i++)
{
if(wanted==a[i])
{
cout<<"found at"<<" "<<i<<" "<<"location"<<endl;
count=count+1;
}
}
if(count==0)
cout<<"The number is not in the list";
else
cout<<"The number is found";
getch();
}
ARRAY AND ITS APPLICATIONS
![ARRAY AND ITS APPLICATIONS]()
Reviewed by Shobhit Goel
on
August 10, 2015
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