How to Access the First Element of a Vector in C++?
In C++, vectors are dynamic arrays that were introduced to replace the traditional arrays. In this article, we’ll learn how to access the first element of a vector in C++.
Example
Input: myVector = {5, 1, 8, 3, 4} Output: First element of myVector is: 5
Access the First Element of a Vector in C++
The std::vector class has the std::vector::front() member function which provides a simple way to access the first element of the vector. We can also simply access the first element using its index which is 0 and [] operator.
C++ Program to Access the First Element in a Vector
C++
// C++ Program to demonstrate accessing the first element of // a vector using front() and [0] #include <iostream> #include <vector> using namespace std; int main() { // Initializing a vector with some elements vector< int > myVector = { 1, 2, 3, 4, 5 }; // Printing the first element using front() cout << "The first element using front(): " << myVector.front() << endl; // Printing the first element using [0] cout << "The first element using myVector[0]: " << myVector[0] << endl; return 0; } |
Output
The first element using front(): 1 The first element using myVector[0]: 1
Time Complexity: O(1), as vector provide random access using index.
Auxilary Space: O(1)
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