The introduction of array class from C++11 has offered a better alternative for C-style arrays. The advantages of array class over C-style array are :-
- Array classes knows its own size, whereas C-style arrays lack this property. So when passing to functions, we don't need to pass size of Array as a separate parameter.
- With C-style array there is more risk of array being decayed into a pointer. Array classes don't decay into pointers
- Array classes are generally more efficient, light-weight and reliable than C-style arrays.
Operations on array :-
1. at() :- This function is used to access the elements of array.
2. get() :- This function is also used to access the elements of array. This function is not the member of array class but overloaded function from class tuple.
3. operator[] :- This is similar to C-style arrays. This method is also used to access array elements.
CPP
// C++ code to demonstrate working of array,
// at() and get()
#include<iostream>
#include<array> // for array, at()
#include<tuple> // for get()
using namespace std;
int main()
{
// Initializing the array elements
array<int,6> ar = {1, 2, 3, 4, 5, 6};
// Printing array elements using at()
cout << "The array elements are (using at()) : ";
for ( int i=0; i<6; i++)
cout << ar.at(i) << " ";
cout << endl;
// Printing array elements using get()
cout << "The array elements are (using get()) : ";
cout << get<0>(ar) << " " << get<1>(ar) << " ";
cout << get<2>(ar) << " " << get<3>(ar) << " ";
cout << get<4>(ar) << " " << get<5>(ar) << " ";
cout << endl;
// Printing array elements using operator[]
cout << "The array elements are (using operator[]) : ";
for ( int i=0; i<6; i++)
cout << ar[i] << " ";
cout << endl;
return 0;
}
OutputThe array elements are (using at()) : 1 2 3 4 5 6
The array elements are (using get()) : 1 2 3 4 5 6
The array elements are (using operator[]) : 1 2 3 4 5 6
4. front() :- This returns reference to the first element of array.
5. back() :- This returns reference to the last element of array.
CPP
// C++ code to demonstrate working of
// front() and back()
#include<iostream>
#include<array> // including header file to use stl array and there function
using namespace std;
int main()
{
// Initializing the array elements
array<int,6> ar = {1, 2, 3, 4, 5, 6};
// Printing first element of array
cout << "First element of array is : ";
int &a=ar.front();
cout <<a<< endl;
// Printing last element of array
cout << "Last element of array is : ";
int &b=ar.back();
cout << b << endl;
//change first and last element of array using these references
a=10; //now 1 change to 10
b=60; //now 6 change to 60
//lets print array now
cout<<"array after updating first and last element \n";
for (auto x: ar)
{
cout<<x<<" ";
}
cout<<endl;
return 0;
}
OutputFirst element of array is : 1
Last element of array is : 6
array after updating first and last element
10 2 3 4 5 60
6. size() :- It returns the number of elements in array. This is a property that C-style arrays lack.
7. max_size() :- It returns the maximum number of elements array can hold i.e, the size with which array is declared. The size() and max_size() return the same value.
CPP
// C++ code to demonstrate working of
// size() and max_size()
#include<iostream>
#include<array> // for size() and max_size()
using namespace std;
int main()
{
// Initializing the array elements
array<int,6> ar = {1, 2, 3, 4, 5, 6};
// Printing number of array elements
cout << "The number of array elements is : ";
cout << ar.size() << endl;
// Printing maximum elements array can hold
cout << "Maximum elements array can hold is : ";
cout << ar.max_size() << endl;
return 0;
}
OutputThe number of array elements is : 6
Maximum elements array can hold is : 6
8. swap() :- The swap() swaps all elements of one array with other.
CPP
// C++ code to demonstrate working of swap()
#include<iostream>
#include<array> // for swap() and array
using namespace std;
int main()
{
// Initializing 1st array
array<int,6> ar = {1, 2, 3, 4, 5, 6};
// Initializing 2nd array
array<int,6> ar1 = {7, 8, 9, 10, 11, 12};
// Printing 1st and 2nd array before swapping
cout << "The first array elements before swapping are : ";
for (int i=0; i<6; i++)
cout << ar[i] << " ";
cout << endl;
cout << "The second array elements before swapping are : ";
for (int i=0; i<6; i++)
cout << ar1[i] << " ";
cout << endl;
// Swapping ar1 values with ar
ar.swap(ar1);
// Printing 1st and 2nd array after swapping
cout << "The first array elements after swapping are : ";
for (int i=0; i<6; i++)
cout << ar[i] << " ";
cout << endl;
cout << "The second array elements after swapping are : ";
for (int i=0; i<6; i++)
cout << ar1[i] << " ";
cout << endl;
return 0;
}
OutputThe first array elements before swapping are : 1 2 3 4 5 6
The second array elements before swapping are : 7 8 9 10 11 12
The first array elements after swapping are : 7 8 9 10 11 12
The second array elements after swapping are : 1 2 3 4 5 6
9. empty() :- This function returns true when the array size is zero else returns false.
10. fill() :- This function is used to fill the entire array with a particular value.
CPP
// C++ code to demonstrate working of empty()
// and fill()
#include<iostream>
#include<array> // for fill() and empty()
using namespace std;
int main()
{
// Declaring 1st array
array<int,6> ar;
// Declaring 2nd array
array<int,0> ar1;
// Checking size of array if it is empty
ar1.empty()? cout << "Array empty":
cout << "Array not empty";
cout << endl;
// Filling array with 0
ar.fill(0);
// Displaying array after filling
cout << "Array after filling operation is : ";
for ( int i=0; i<6; i++)
cout << ar[i] << " ";
return 0;
}
OutputArray empty
Array after filling operation is : 0 0 0 0 0 0
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