C++ .front()

In C++, the .front() method returns a reference to the first element in the deque.

Syntax

deque_name.front()

Parameters:

.front() does not take any parameters

Return value:

• Returns a reference to the first element of the deque.
  • For a non-const deque, returns T& (modifiable).
  • For a const deque, returns const T& (read-only).

Example

The example below demonstrates use of .front() to access the first element in a deque:

#include <iostream>
#include <deque>

int main() {
  // Create a deque of integers
  std::deque<int> numbers;

  // Add some elements to the deque
  numbers.push_back(100);
  numbers.push_back(200);
  numbers.push_back(300);

  // Access the first element using .front()
  std::cout << "First element: " << numbers.front() << std::endl;

  // Modify the first element
  numbers.front() = 50;

  // Display updated deque contents
  std::cout << "Updated deque: ";
  for (int num : numbers) {
    std::cout << num << " ";
  }
  std::cout << std::endl;

  return 0;
}

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The output of this program will be:

First element: 100
Updated deque: 50 200 300

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This shows that .front() allows both access and modification of the deque’s first element.

Codebyte Example

Run the following codebyte example to understand the use of .front() method:

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