Common methods of vector container

• Introduction to Containers
  • Definition and initialization
  • Insert element at end
  • Traversing the size function can be dynamically incremented
  • Adding vector content by subscript operation is not a safe operation
  • The subscript operation for an existing element only does not exist crash
  • Copying an element to another container type must match the container type and the element type must be the same
• Introduction to Iterators
  • Defined
  • Begin and end operations
  • Self-increment and dereference operations for iterators
  • Arithmetic operations of iterators
  • Const_iterator Read Only

Container Introduction Definition and initialization

vector<int> vec(5,100);vector<string> strVec(10,"hello");

Insert element at end

  vec.push_back(102);  strVec.push_back("what");

Traversing the size () function can be dynamically incremented

     for( vector<int>:: Size_type ix=0; Ix<vec.size (); ix++) {cout<<vec[ix]<<endl; Vec.push_back (ix+Ten);cout<<"Size is"<<vec.size () <<endl;if(vec.size () = =Ten)        { Break; }    } for( vector<string>:: Size_type jx=0; Jx<strvec.size (); jx++) {cout<<strVec[jx]<<endl; }

Increase vector content by subscript operation, not safe operation

vector <int> vec2(10);    cout<<vec2[9]<<endl;    cout<<vec2[10]<<endl;

Only the existing elements can be subscript, there is no crash

vector<int> emptyVec;//cout<<emptyVec[0]<<endl;    error

Copy element one container to another container, type must match, container type and element type must be the same

    vector<int> vecCopy(vec);    for(vector<int>::size_type i=0;i<vecCopy.size();i++)    {      cout<<vecCopy[i]<<endl;    }

Introduction to Iterators

Iterators are supported for all standard library containers, but only a handful of containers support subscript operations

Defined

    vector<int>::iterator iter;

Begin and end operations

Begin returns the first position that the iterator points to, and end points to the next of the vector's end elements

vector<string>::iterator iBegin=strVec.begin();vector<string>::iterator iEnd=strVec.end();

Self-increment and dereference operations for iterators

++iter points to the second element
*iter point to current element

    cout<<*iBegin<<endl;    cout<<*(iEnd-1)<<endl;     for(;iBegin<iEnd;iBegin++)    {      cout<<*iBegin<<endl;    }

Arithmetic operations of iterators

Iter+n Iter-n
Iter1-iter2

    string str("richard");    *(iBegin+3)=str;    cout<<*(iBegin+3)<<endl;        cout<<iEnd-iBegin<<endl;        vector<string>::iterator              mid=iBegin+strVec.size()/2;    cout<<*mid<<endl;

Const_iterator Read Only

Common methods of vector container