std::vector back() method

od C++20

// prism-push-types:reference,const_reference
// Non const version
constexpr reference       back();

// Const version
constexpr const_reference back() const;

do C++20

// prism-push-types:reference,const_reference
// Non const version
reference       back();

// Const version
const_reference back() const;

Returns a reference

to the last element in the container.

Undefined Behavior

Calling back() on an empty container is undefined behavior

.

Parameters

(none)

Return value

Reference to the last element.

Complexity

Constant - O(1).

Notes

For a container c, the expression c.back() is equivalent to *std::prev(c.end()) and c[c.size() - 1].

Example

Main.cpp

#include <array>
#include <iostream>
 
int main()
{
    std::vector<char> letters {'o', 'm', 'g', 'w', 't', 'f'};
 
    if (!letters.empty()) {
        std::cout << "The last character is '" << letters.back() << "'.\n";
    }  
}

Output

The last character is 'f'.