📄 assign.html
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html><head> <meta name="generator" content= "HTML Tidy for Linux/x86 (vers 1 September 2005), see www.w3.org"> <title>assign</title> <link href="../cppreference.css" rel="stylesheet" type="text/css"></head><body><table> <tr> <td> <div class="body-content"> <div class="header-box"> <a href="../index.html">cppreference.com</a> > <a href= "index.html">C++ Vectors</a> > <a href="assign.html">assign</a> </div> <div class="name-format"> assign </div> <div class="syntax-name-format"> Syntax: </div> <pre class="syntax-box"> #include <vector> void assign( <strong>size_type</strong> num, const <a href="../containers.html">TYPE</a>& val ); void assign( <a href="../iterators.html">input_iterator</a> start, <a href="../iterators.html">input_iterator</a> end );</pre> <p>The assign() function either gives the current vector the values from <em>start</em> to <em>end</em>, or gives it <em>num</em> copies of <em>val</em>.</p> <p>This function will destroy the previous contents of the vector.</p> <p>For example, the following code uses assign() to put 10 copies of the integer 42 into a vector:</p> <pre class="example-code"> vector<int> v; v.assign( 10, 42 ); for( int i = 0; i < v.size(); i++ ) { cout << v[i] << " "; } cout << endl; </pre> <p>The above code displays the following output:</p> <pre class="example-code"> 42 42 42 42 42 42 42 42 42 42 </pre> <p>The next example shows how assign() can be used to copy one vector to another:</p> <pre class="example-code"> vector<int> v1; for( int i = 0; i < 10; i++ ) { v1.push_back( i ); } vector<int> v2; v2.assign( v1.begin(), v1.end() ); for( int i = 0; i < v2.size(); i++ ) { cout << v2[i] << " "; } cout << endl; </pre> <p>When run, the above code displays the following output:</p> <pre class="example-code"> 0 1 2 3 4 5 6 7 8 9 </pre> <div class="related-name-format"> Related topics: </div> <div class="related-content"> (C++ Strings) <a href="../cppstring/assign1.html">assign</a><br> <a href="insert.html">insert</a><br> <a href="push_back.html">push_back</a><br> (C++ Lists) <a href="../cpplist/push_front.html">push_front</a> </div> </div> </td> </tr> </table></body></html>⌨️ 快捷键说明
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