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;} |
The 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;} |
First 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;} |
The 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 arrayusing 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;} |
The 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;} |
Array empty Array after filling operation is : 0 0 0 0 0 0
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