Vector applications (element traversal, insertion, deletion, switching, etc.), vector

Vector applications (element traversal, insertion, deletion, switching, etc.), vector
Here is a summary of some common applications of vector containers. For the vector constructor and initialization, refer to http://blog.csdn.net/lsh_2013/article/details/21191289. Element Traversal

Use an iterator to access a vector Element

#include <vector>#include <iostream>using namespace std;int main(void){vector<int> v;v.push_back(42);v.push_back(51);v.push_back(69);vector<int>::iterator i,iend;iend=v.end();int j;for(i=v.begin(),j=0; i!=iend; i++,j++)    cout<<"v[" << j << "] = " << *i<< endl;return 0;}

Element insertion

Iterator insert (iteratorpos, const T & x); // insert an element x before the element indicated by the iterator pos

# Include <vector> # include <iostream> using namespace std; int main (void) {vector <int> v; v. push_back (6); v. push_back (7); v. push_back (8); v. push_back (10); v. insert (v. begin () + 3, 9); // insert v before the element. insert (v. begin (), 5); // Insert the first element v. insert (v. end (), 11); // Insert the last element for (int I = 0; I <v. size (); I ++) cout <"v [" <I <"] =" <v [I] <endl; return 0 ;}

Element Deletion

1) iterator erase (iterator pos); // Delete the elements referred to by the iterator pos

2) iterator erase (iterator first, iterator last); // delete all elements in the iteration interval [first, last)

# Include <iostream> # include <vector> using namespace std; int main () {vector <int> myvector; for (int I = 1; I <= 10; I ++) myvector. push_back (I); // Delete the first element myvector. erase (myvector. begin () + 5); // Delete the previous element myvector. erase (myvector. begin (), myvector. begin () + 3); cout <"myvector contains:"; for (unsigned I = 0; I <myvector. size (); ++ I) cout <''<myvector [I]; cout <'\ n'; return 0 ;}

Reverse traversal of Elements

#include <vector>#include <iostream>using namespace std;   int main(void){vector<int> v;v.push_back(1);v.push_back(3);v.push_back(5);v.push_back(7);v.push_back(9);vector<int>::reverse_iterator ri,riend;riend=v.rend();for(ri=v.rbegin();ri!=riend;ri++)cout << *ri << endl;return 0;}

Vector Switching

Void swap (vector & x); // element exchange between two vector containers

# Include <iostream> # include <vector> using namespace std; int main () {vector <int> v1 (2, 10 ); // 10 10 vector <int> v2 (3, 30); // 30 30 30 cout <"v1 contains:"; for (unsigned I = 0; I <v1.size (); I ++) cout <''<v1 [I]; cout <'\ n'; cout <" v2 contains: "; for (unsigned I = 0; I <v2.size (); I ++) cout <''<v2 [I]; cout <'\ n'; v1.swap (v2 ); // switch cout <"After switch" <endl; cout <"v1 contains:"; for (unsigned I = 0; I <v1.size (); I ++) cout <''<v1 [I]; cout <'\ n'; cout <" v2 contains: "; for (unsigned I = 0; I <v2.size (); I ++) cout <''<v2 [I]; cout <'\ n'; return 0 ;}

Other common functions

1) bool empty ();

// Determine whether the vector container is empty. If the container does not have one element, true is returned; otherwise, false is returned.

2) size_type size ();

// The actual number of elements in the current vector container.

3) size_typemax_size ();

// The maximum number of elements allowed by the system in the vector container.

4) size_typecapacity ();

// The number of elements that can accommodate a vector.

5) reference front ()

// The first element (reference) of the vector container. The vector must not be empty.

6) reference back ();

// Returns the last element (reference) of the vector container. The vector must not be empty.

7) void pop_back ();

// Delete a container element at the end.

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