array at() function in C++ STL
The array::at() is a built-in function in C++ STL which returns a reference to the element present at location i in given array.
Syntax:
array_name.at(i)
Parameters: The function accepts a single mandatory parameter i which specifies the location.
Return value: The function returns an element present at index i in given array if i is valid index otherwise it throws out_of_range exception.
Time Complexity: O(1)
Below programs demonstrate the array::at() function:
Program 1:
// CPP program to illustrate // the array::at() function #include <bits/stdc++.h> using namespace std; int main() { // array initialisation array<int, 5> arr = { 1, 5, 2, 4, 7 }; // prints the element at ith index // index starts from zero cout << "The element at index 2 is " << arr.at(2) << endl; return 0; } |
Output:
The element at index 2 is 2
Program 2 : Illustrating function when it is implemented on lesser size array causing an error.
// CPP program to illustrate // the array::at() function #include <bits/stdc++.h> using namespace std; int main() { // array initialisation array<int, 5> arr = { 1, 5, 2, 4, 7 }; // it is an exception cout << "The element at index 2 is " << arr.at(7) << endl; return 0; } |
Output:
Abort signal from abort(3) (SIGABRT)
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