C++ .back()

In C++, the .back() method returns a reference to the last element in a deque. It allows direct access to that element for reading or modifying without removing it.

Note: Calling .back() on an empty deque leads to undefined behavior. Check with .empty() before using .back().

Syntax

dequeName.back();

Parameters:

This method does not take any parameters.

Return value:

Returns a reference to the last element of the deque. If the deque is const, it returns a const reference.

Example: Accessing and Updating the Last Element

This example retrieves the last number in a deque, updates it, and displays the change:

#include <deque>
#include <iostream>

int main() {
  std::deque<int> scores = {45, 67, 89};

  std::cout << "Last score: " << scores.back() << std::endl;

  // Update the last element
  scores.back() = 100;

  std::cout << "Updated last score: " << scores.back() << std::endl;
  return 0;
}

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This program produces the following output:

Last score: 89
Updated last score: 100

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Codebyte Example: Using .back() in a Conditional Check

This example shows how .back() can be used to verify or modify the final value in a deque:

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