Vector class element at, erase, insert functions. - C++ STL

C++ examples for STL:vector

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Description

Vector class element at, erase, insert functions.

Demo Code

#include <iostream> 
#include <vector> 
#include <algorithm>
#include <iterator> 
#include <stdexcept> 
using namespace std; 

int main() //from  w ww  .  ja  va  2  s . com
{ 
    const int SIZE = 6; 
    int array[ SIZE ] = { 1, 2, 3, 4, 5, 6 }; 
    vector< int > integers( array, array + SIZE ); 
    ostream_iterator< int > output( cout, " " ); 

    cout << "Vector integers contains: "; 
    copy( integers.begin(), integers.end(), output ); 

    cout << "\nFirst element of integers: " << integers.front() 
       << "\nLast element of integers: " << integers.back(); 

    integers[ 0 ] = 7; // set first element to 7 
    integers.at( 2 ) = 10; // set element at position 2 to 10 

    // insert 22 as 2nd element 
    integers.insert( integers.begin() + 1, 22 ); 

    cout << "\n\nContents of vector integers after changes: "; 
    copy( integers.begin(), integers.end(), output ); 

    // access out-of-range element 
    try 
    { 
       integers.at( 100 ) = 777; 
    }
    catch ( out_of_range &outOfRange ) // out_of_range exception 
    { 
       cout << "\n\nException: " << outOfRange.what(); 
    }

    // erase first element 
    integers.erase( integers.begin() ); 
    cout << "\n\nVector integers after erasing first element: "; 
    copy( integers.begin(), integers.end(), output ); 

    // erase remaining elements 
    integers.erase( integers.begin(), integers.end() ); 
    cout << "\nAfter erasing all elements, vector integers " 
       << ( integers.empty() ? "is" : "is not" ) << " empty"; 

    // insert elements from array 
    integers.insert( integers.begin(), array, array + SIZE ); 
    cout << "\n\nContents of vector integers before clear: "; 
    copy( integers.begin(), integers.end(), output ); 

    // empty integers; clear calls erase to empty a collection 
    integers.clear(); 
    cout << "\nAfter clear, vector integers " << ( integers.empty() ? "is" : "is not" ) << " empty" << endl; 
    
}

Result


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