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从www.CppReference.com打包的C++参考手册

  <p>For example, in the following code, the first "cout" statement
  will display garbage, whereas the second statement will actually
  display the last element of the vector:</p>

  <pre class="example-code">
  vector&lt;int&gt; v1;
  v1.push_back( 0 );
  v1.push_back( 1 );
  v1.push_back( 2 );
  v1.push_back( 3 );

  int bad_val = *(v1.end());
  cout &lt;&lt; "bad_val is " &lt;&lt; bad_val &lt;&lt; endl;

  int good_val = *(v1.end() - 1);
  cout &lt;&lt; "good_val is " &lt;&lt; good_val &lt;&lt; endl;
</pre>

  <p>The next example shows how <a href= "begin.html">begin</a>() and
  end() can be used to iterate through all of the members of a
  vector:</p> <pre class="example-code"> vector&lt;int&gt; v1( 5, 789
  ); vector&lt;int&gt;::iterator it; for( it = v1.begin(); it !=
  v1.end(); it++ ) { cout &lt;&lt; *it &lt;&lt; endl; } </pre>

  <p>The iterator is initialized with a call to <a href=
  "begin.html">begin</a>(). After the body of the loop has been
  executed, the iterator is incremented and tested to see if it is
  equal to the result of calling end(). Since end() returns an iterator
  pointing to an element just after the last element of the vector, the
  loop will only stop once all of the elements of the vector have been
  displayed.</p>

  <p>end() runs in <a href="../complexity.html">constant time</a>.</p>

  <div class="related-name-format">
    Related topics:
  </div>

  <div class="related-content">
    <a href="begin.html">begin</a><br>
    <a href="rbegin.html">rbegin</a><br>
    <a href="rend.html">rend</a>
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<hr>

  <div class="name-format">
    erase
  </div>

  <div class="syntax-name-format">
    Syntax:
  </div>
  <pre class="syntax-box">
  #include &lt;vector&gt;
  iterator erase( iterator loc );
  iterator erase( iterator start, iterator end );
</pre>

  <p>The erase() function either deletes the element at location
  <em>loc</em>, or deletes the elements between <em>start</em> and
  <em>end</em> (including <em>start</em> but not including
  <em>end</em>). The return value is the element after the last element
  erased.</p>

  <p>The first version of erase (the version that deletes a single
  element at location <em>loc</em>) runs in <a href=
  "../complexity.html">constant time</a> for lists and <a href=
  "../complexity.html">linear time</a> for vectors, dequeues, and
  strings. The multiple-element version of erase always takes <a href=
  "../complexity.html">linear time</a>.</p>

  <p>For example:</p>
  <pre class="example-code">
  // Create a vector, load it with the first ten characters of the alphabet
  vector&lt;char&gt; alphaVector;
  for( int i=0; i &lt; 10; i++ ) {
    alphaVector.push_back( i + 65 );
  }
  int size = alphaVector.size();
  vector&lt;char&gt;::iterator startIterator;
  vector&lt;char&gt;::iterator tempIterator;
  for( int i=0; i &lt; size; i++ ) {
    startIterator = alphaVector.begin();
    alphaVector.erase( startIterator );
    // Display the vector
    for( tempIterator = alphaVector.begin(); tempIterator != alphaVector.end(); tempIterator++ ) {
      cout &lt;&lt; *tempIterator;
    }
    cout &lt;&lt; endl;
  }              
</pre>

  <p>That code would display the following output:</p>
  <pre class="example-code">
  BCDEFGHIJ
  CDEFGHIJ
  DEFGHIJ
  EFGHIJ
  FGHIJ
  GHIJ
  HIJ
  IJ
  J              
</pre>

  <p>In the next example, erase() is called with two iterators to
  delete a range of elements from a vector:</p>
  <pre class="example-code">
  // create a vector, load it with the first ten characters of the alphabet
  vector&lt;char&gt; alphaVector;
  for( int i=0; i &lt; 10; i++ ) {
    alphaVector.push_back( i + 65 );
  }
  // display the complete vector
  for( int i = 0; i &lt; alphaVector.size(); i++ ) {
    cout &lt;&lt; alphaVector[i];
  }
  cout &lt;&lt; endl;            

  // use erase to remove all but the first two and last three elements
  // of the vector
  alphaVector.erase( alphaVector.begin()+2, alphaVector.end()-3 );
  // display the modified vector
  for( int i = 0; i &lt; alphaVector.size(); i++ ) {
    cout &lt;&lt; alphaVector[i];
  }
  cout &lt;&lt; endl;            
</pre>

  <p>When run, the above code displays:</p>
  <pre class="example-code">
  ABCDEFGHIJ
  ABHIJ          
</pre>

  <div class="related-name-format">
    Related topics:
  </div>

  <div class="related-content">
    <a href="clear.html">clear</a><br>
    <a href="insert.html">insert</a><br>
    <a href="pop_back.html">pop_back</a><br>
    (C++ Lists) <a href="../cpplist/pop_front.html">pop_front</a><br>
    (C++ Lists) <a href="../cpplist/remove.html">remove</a><br>
    (C++ Lists) <a href="../cpplist/remove_if.html">remove_if</a>
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<hr>

  <div class="name-format">
    front
  </div>

  <div class="syntax-name-format">
    Syntax:
  </div>
  <pre class="syntax-box">
  #include &lt;vector&gt;
  <a href="../containers.html">TYPE</a>&amp; front();
  const <a href="../containers.html">TYPE</a>&amp; front() const;
</pre>

  <p>The front() function returns a reference to the first element of
  the vector, and runs in <a href="../complexity.html">constant
  time</a>.</p>

  <p>For example, the following code uses a vector and the <a
  href="../cppalgorithm/sort.html">sort() algorithm</a> to display the
  first word (in alphabetical order) entered by a user:</p>

  <pre class="example-code">
  vector<string> words;
  string str;
  
  while( cin >> str ) words.push_back(str);

  sort( words.begin(), words.end() );

  cout << "In alphabetical order, the first word is '" << words.front() << "'." << endl;
</pre>

  <p>When provided with this input:</p>
  <pre class="example-code">
  now is the time for all good men to come to the aid of their country
</pre>

  <p>...the above code displays:</p>
  <pre class="example-code">
  In alphabetical order, the first word is 'aid'.
</pre>

  <div class="related-name-format">
    Related topics:
  </div>

  <div class="related-content">
    <a href="back.html">back</a><br>
    (C++ Lists) <a href="../cpplist/pop_front.html">pop_front</a><br>
    (C++ Lists) <a href="../cpplist/push_front.html">push_front</a>
  </div>
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<hr>

  <div class="name-format">
    insert
  </div>

  <div class="syntax-name-format">
    Syntax:
  </div>
  <pre class="syntax-box">
  #include &lt;vector&gt;
  iterator insert( iterator loc, const <a href=
"../containers.html">TYPE</a>&amp; val );
  void insert( iterator loc, <strong>size_type</strong> num, const <a href="../containers.html">TYPE</a>&amp; val );
  template&lt;<a href=
"../containers.html">TYPE</a>&gt; void insert( iterator loc, <a href=
"../iterators.html">input_iterator</a> start, <a href=
"../iterators.html">input_iterator</a> end );
</pre>

  <p>The insert() function either:</p>

  <ul>
    <li>inserts <em>val</em> before <em>loc</em>, returning an iterator
    to the element inserted,</li>

    <li>inserts <em>num</em> copies of <em>val</em> before
    <em>loc</em>, or</li>

    <li>inserts the elements from <em>start</em> to <em>end</em> before
    <em>loc</em>.</li>
  </ul>

  <p>Note that inserting elements into a vector can be relatively
  time-intensive, since the underlying data structure for a vector is
  an array.  In order to insert data into an array, you might need to
  displace a lot of the elements of that array, and this can take <a
  href="../complexity.html">linear time</a>.  If you are planning on
  doing a lot of insertions into your vector and you care about speed,
  you might be better off using a container that has a linked list as
  its underlying data structure (such as a <a
  href="../cpplist/index.html">List</a> or a
  <a
  href="../cppdeque/index.html">Deque</a>).</p>

  <p>For example, the following code uses the insert() function to
  splice four copies of the character 'C' into a vector of
  characters:</p>

  <pre class="example-code">
 // Create a vector, load it with the first 10 characters of the alphabet
 vector&lt;char&gt; alphaVector;
 for( int i=0; i &lt; 10; i++ ) {
   alphaVector.push_back( i + 65 );
 }              

 // Insert four C&#39;s into the vector
 vector&lt;char&gt;::iterator theIterator = alphaVector.begin();
 alphaVector.insert( theIterator, 4, &#39;C&#39; );             

 // Display the vector
 for( theIterator = alphaVector.begin(); theIterator != alphaVector.end(); theIterator++ )    {
   cout &lt;&lt; *theIterator;
 }              
</pre>

  <p>This code would display:</p>
  <pre class="example-code">
 CCCCABCDEFGHIJ         
</pre>

  <p>Here is another example of the insert() function.  In this code,
  insert() is used to append the contents of one vector onto the end
  of another:</p>

  <pre class="example-code">
  vector&lt;int&gt; v1;
  v1.push_back( 0 );
  v1.push_back( 1 );
  v1.push_back( 2 );
  v1.push_back( 3 );

  vector&lt;int&gt; v2;
  v2.push_back( 5 );
  v2.push_back( 6 );
  v2.push_back( 7 );
  v2.push_back( 8 );

  cout &lt;&lt; "Before, v2 is: ";
  for( int i = 0; i &lt; v2.size(); i++ ) {
    cout &lt;&lt; v2[i] &lt;&lt; " ";
  }
  cout &lt;&lt; endl;

  v2.insert( v2.end(), v1.begin(), v1.end() );

  cout &lt;&lt; "After, v2 is: ";
  for( int i = 0; i &lt; v2.size(); i++ ) {
    cout &lt;&lt; v2[i] &lt;&lt; " ";
  }
  cout &lt;&lt; endl;
</pre>

  <p>When run, this code displays:</p>

  <pre class="example-code">
  Before, v2 is: 5 6 7 8
  After, v2 is: 5 6 7 8 0 1 2 3
</pre>


  <div class="related-name-format">
    Related topics:
  </div>

  <div class="related-content">
    <a href="assign.html">assign</a><br>
    <a href="erase.html">erase</a><br>
    <a href="push_back.html">push_back</a><br>
    (C++ Lists) <a href="../cpplist/merge.html">merge</a><br>
    (C++ Lists) <a href="../cpplist/push_front.html">push_front</a><br>
    (C++ Lists) <a href="../cpplist/splice.html">splice</a>
  </div>
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<hr>

  <div class="name-format">
    max_size
  </div>

  <div class="syntax-name-format">
    Syntax:
  </div>
  <pre class="syntax-box">
  #include &lt;vector&gt;
  <strong>size_type</strong> max_size() const;
</pre>

  <p>The max_size() function returns the maximum number of elements
  that the vector can hold. The max_size() function should not be
  confused with the <a href="size.html">size</a>() or <a href=
  "capacity.html">capacity</a>() functions, which return the number of
  elements currently in the vector and the the number of elements that
  the vector will be able to hold before more memory will have to be
  allocated, respectively.</p>

  <div class="related-name-format">
    Related topics:
  </div>

  <div class="related-content">
    <a href="size.html">size</a>
  </div>
  </div>
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<hr>

  <div class="name-format">
    pop_back
  </div>

  <div class="syntax-name-format">
    Syntax:
  </div>
  <pre class="syntax-box">
  #include &lt;vector&gt;
  void pop_back();
</pre>

  <p>The pop_back() function removes the last element of the
  vector.</p>

  <p>pop_back() runs in <a href="../complexity.html">constant
  time</a>.</p>

  <div class="related-name-format">
    Related topics:
  </div>

  <div class="related-content">
    <a href="back.html">back</a><br>
    <a href="erase.html">erase</a><br>
    (C++ Lists) <a href="../cpplist/pop_front.html">pop_front</a><br>
    <a href="push_back.html">push_back</a>
  </div>
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  </table>
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<hr>

  <div class="name-format">
    push_back
  </div>

  <div class="syntax-name-format">
    Syntax:
  </div>
  <pre class="syntax-box">
  #include &lt;vector&gt;
  void push_back( const <a href=
"../containers.html">TYPE</a>&amp; val );
</pre>

  <p>The push_back() function appends <em>val</em> to the end of the
  vector.</p>