C++ vector容器基本操作小练_vector<string> s(s1.begin(),s1.end())-优快云博客

本文详细介绍了C++中标准模板库(STL)的vector容器的各种操作方法，包括元素的添加、删除、查找以及容器的调整等。通过具体实例展示了如何使用迭代器遍历容器，并演示了容量与大小的区别及调整技巧。

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#include <iostream>
#include <vector>

using namespace std;
int main()
{
    string s;
    vector<string> s1;
    int i=5;
    
    /*
    往容器里面存放元素 
    */
    while( i>0 )
    {
           cin >> s;
           s1.push_back(s);
           --i;
    }
    cout << s1.size() << endl;
    
    /*
    声明迭代器 
    */
    vector<string>::iterator it;
           
    for( it=s1.begin(); it!=s1.end(); ++it)
    {
         cout << *it << "  ";
    }
    
    /*
    往容器里面插入元素 
    */ 
    s1.insert(s1.begin(), "......");
    cout << endl;
    
    for( it=s1.begin(); it!=s1.end(); ++it)
    {
         cout << *it << "  ";
    }
    
    cout << endl << s1.at(1);
    
    /*
    删除尾端元素 
    */
    s1.pop_back();
    s1.pop_back();
    s1.pop_back();
    
    cout << endl;
    for( it=s1.begin(); it!=s1.end(); ++it)
    {
         cout << *it << "  ";
    }
    
    /*
    删除某个迭代器指定的元素 
    */
    it=s1.begin();
    s1.erase(it+2);
    cout << endl;
    for( it=s1.begin(); it!=s1.end(); ++it)
    {
         cout << *it << "  ";
    }
    
    /*
    重新设置容器大小 
    */
    s1.resize(20, "wang");
    cout << endl;
    for( it=s1.begin(); it!=s1.end(); ++it)
    {
         cout << *it << "  ";
    }
    
    
    /*
    傻瓜循环，删除偶数元素，复制每个奇数元素 
    */
    vector<int> vi;
    for(int i=0; i<10; ++i)
    {
            vi.push_back(i);
    }
    vector<int>::iterator iter = vi.begin();
    while( iter != vi.end() )
    {
           if( *iter %2 )
           {
               iter = vi.insert(iter, *iter);
               iter += 2;
           } 
           else
           {
               iter = vi.erase(iter);
           }
    }
    cout << endl;
    for( iter=vi.begin(); iter != vi.end(); ++iter)
    {
         cout << *iter << "  ";
    }
    cout << endl;
    
    
    vector<int>::iterator begin = vi.begin();
    while( begin != vi.end() )
    {
           ++begin;
           begin = vi.insert(begin, 42);
           ++begin;
    }
    cout << endl;
    for( iter=vi.begin(); iter != vi.end(); ++iter)
    {
         cout << *iter << "  ";
    }
    cout << endl;
    
    /*
    capacity和size 
    */
    vector<int> ivec;
    cout << endl;
    cout << "ivec: size: " << ivec.size()
         << " capacity: " << ivec.capacity() <<endl;
         
    for( vector<int>::size_type ix = 0; ix != 24; ++ix)
    {
         ivec.push_back(ix);
    }
    cout << "ivec: size: " << ivec.size()
         << " capacity: " << ivec.capacity() <<endl;
    
    ivec.reserve(50);
    cout << "ivec: size: " << ivec.size()
         << " capacity: " << ivec.capacity() <<endl;
         
    while( ivec.size() != ivec.capacity() )
    {
           ivec.push_back(0); 
    }
    cout << "ivec: size: " << ivec.size()
         << " capacity: " << ivec.capacity() <<endl;
         
    ivec.push_back(44);
    cout << "ivec: size: " << ivec.size()
         << " capacity: " << ivec.capacity() <<endl << endl;
    
    vector<int>::iterator v;
    v = ivec.begin();
    while( v!= ivec.end() )
    {
           cout << *v << " ";
           ++v; 
    }
    
    cin >> i;
    return 0;
}