Summary of the basic usage of STL container vector and stl container vector

Summary of the basic usage of STL container vector and stl container vector

According to ACM program design, we use examples to demonstrate vector usage.

Methods: push_back (), insert (), erase (), clear (), size (), empty ();

Algorithm: reverse (), sort (), accumulate ().

1 # include <vector> 2 # include <iostream> 3 # include <algorithm> // sort, reverse algorithm 4 # include <numeric> // accumulate algorithm 5 using namespace std; 6 template <typename T> 7 void printVec (const vector <T> & v) {// function template output vector 8 for (int I = 0; I <v. size (); I ++) 9 cout <v [I] <''; 10 cout <endl; 11} 12 13 int main () {14 vector <int> iv; // defines the vector 15 iv. push_back (2); // append new elements to the end 16 iv. push_back (7); 17 iv. push_back (3); 18 iv. Push_back (4); 19 iv. push_back (1); 20 iv. push_back (9); 21 cout <iv [2] <endl; // subscript access element 22 23 vector <double> dv (3 ); // defines the vector 24 cout <dv [2] <endl; // The default value is 0 25 26 vector <double> dv1 (6, 7.18 ); // define the vector 27 cout <dv1 [2] <endl; // default value: 7.1828 29 vector <int>: iterator it; // iterator output vector 30 for (it = iv. begin (); it! = Iv. end (); it ++) 31 cout <* it <''; 32 cout <endl; 33 cout <accumulate (iv. begin (), iv. end (), 0); 34 // use accumulate to sum 35 36 iv. insert (iv. begin (), 8); // insert 837 iv before the first element. insert (iv. begin () + 3rd); // insert 638 iv before elements. insert (iv. end (), 5); // insert 539 printVec (iv) before the last element; // call the printVec function 40 41 dv1.erase (dv1.begin () + 3 ); // delete an element 42 printVec (dv1); 43 44 45 dv1.erase (dv1.begin () + 2, dv1.end ()-1 ); // Delete multiple elements (including the left value but not the right value) 46 printVec (dv1); 47 cout <endl; 48 49 dv1.clear (); // empty the vector 50 cout <dv1.size () <''<dv1.empty () <endl; 51 // returns the number of elements/whether the vector is null 52 53 reverse (iv. begin (), iv. end (); // use the reverse Sorting Algorithm 54 printVec (iv); 55 56 sort (iv. begin (), iv. end (); // use sort to sort 57 printVec (iv) in ascending order; 58 return 0; 59}