map容器插入元素

  
  
//插入元素 //四种插入方法比较
void display()
{
map< int, string> m;

pair< map< int, string>::iterator, bool> pair1 ,pair2,pair3;

//1.方法
pair1 = m.insert(pair< int, string>( 1, "teacher01"));
pair2 = m.insert(pair< int, string>( 2, "teacher02"));
pair3 = m.insert(pair< int, string>( 2, "teacher02"));

if (pair2.second)
{
cout<< "2 teacher02插入成功"<< endl;
cout<<pair2.first->first<< ":"<<pair2.second<< endl;
}
else
{
cout<< "2 teacher02插入失败"<< endl;
cout<<pair2.first->first<< ":"<<pair2.second<< endl;
}

if (pair3.second)
{
cout<< "2 teacher02插入成功"<< endl;
cout<<pair3.first->first<< ":"<<pair3.second<< endl;
}
else
{
cout<< "2 teacher02插入失败"<< endl;
cout<<pair3.first->first<< ":"<<pair3.second<< endl;
}

//2.方法

m.insert(make_pair( 3, "teacher03"));
m.insert(make_pair( 4, "teacher04"));

//3.方法
m.insert( map< int, string>::value_type( 5, "teacher05"));
m.insert( map< int, string>::value_type( 6, "teacher06"));

//4. 如果key相等 会修改对应的value
m[ 7] = "teacher07";
m[ 8] = "teacher08";
m[ 0] = "teacher09";
m[ 0] = "teacher00";

//遍历
for ( map< int, string>::iterator it = m.begin();it!=m.end();it++)
{
cout<<(*it).first<< endl;
cout<<(*it).second<< endl;
}
while (!m.empty())
{
map< int, string>::iterator it = m.begin();
cout<<it->first<< "\t"<<it->second<< endl;
m.erase(it);
}
}
  
  

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