C++ STL 分配器

分配器

  1. #include <iostream>
  2. #include <vector>
  4. using namespace std;
  6. // 分配器
  7. const int NUM = 5;
  8. void useVector(){
  9.     vector<int> rating(NUM);
  10.     vector<double > titles(NUM);
  11.     cout << "You will do ecactly as told. You will enter\n" << NUM << "book titles and your rating(0-10).\n";
  12.     for (int i = 0; i < NUM; i++) {
  13.         cout << "Enter title # " << i + 1 << ": ";
  14.         cin >> titles[i];
  15.         cout << "Enter your rating (0-10): ";
  16.         cin >> rating[i];
  17.         cin.get();
  18.     }
  19.     cout << "Thank you. You entered the following: \n" << "Rating\tBook\n";
  20.     for (int i = 0; i < NUM; i++) {
  21.         cout << rating[i] << "\t" << titles[i] << endl;
  22.     }
  23. }
  25. int main() {
  26.     useVector();
  27.     return 0;
  28. }

STL函数的用法

  1. #include <iostream>
  2. #include <algorithm>
  4. using namespace std;
  6. // STL函数的用法
  7. struct Review{
  8.     string title;
  9.     int rating;
  10. };
  12. bool operator<(const Review & r1, const Review & r2);
  13. bool worseThan(const Review & r1, const Review & r2);
  14. bool FillReview(Review & rr);
  15. void ShowReview(const Review & rr);
  17. bool operator<(const Review & r1, const Review & r2){
  18.     if (r1.title < r2.title)
  19.         return true;
  20.     else if (r1.title == r2.title && r1.rating < r2.rating)
  21.         return false;
  22.     else
  23.         return false;
  24. }
  26. bool worseThan(const Review & r1, const Review & r2){
  27.     if (r1.rating < r2.rating)
  28.         return true;
  29.     else
  30.         return false;
  31. }
  33. bool FillReview(Review & rr){
  34.     cout << "Enter book title(quit to quit): ";
  35.     getline(cin, rr.title);
  36.     if (rr.title == "quit")
  37.         return false;
  38.     cout << "Enter book rating: ";
  39.     cin >> rr.rating;
  40.     if (!cin)
  41.         return false;
  42.     cin.get();
  43.     return true;
  44. }
  46. void ShowReview(const Review & rr){
  47.     cout << rr.rating << "\t" << rr.title << endl;
  48. }
  51. void stlFunction(){
  52.     vector<Review> books;
  53.     Review temp;
  54.     while (FillReview(temp))
  55.         books.push_back(temp);
  56.     cout << "Thanks ,you entered the following " << books.size() << " rating:\n" << "Rating\tBook\n";
  57.     for_each(books.begin(), books.end(), ShowReview);
  58.     sort(books.begin(), books.end());
  59.     cout << "Sorted by title : \nRating\tBook\n";
  60.     for_each(books.begin(), books.end(), ShowReview);
  61.     sort(books.begin(), books.end(), worseThan);
  62.     cout << "Sorted by rating : \nRating\tBook\n";
  63.     for_each(books.begin(), books.end(), ShowReview);
  64.     cout << "Bye.\n";
  65. }
  67. int main() {
  68.     stlFunction();
  69.     return 0;
  70. }

迭代器的使用

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  5. using namespace std;
  7. // 迭代器
  8. void useIterator(){
  9.     int casts[10] = {6, 7, 2, 9, 4, 11, 8, 7, 10, 5};
  10.     vector<int > dice(10);
  11.     // copy from to vector
  12.     copy(casts, casts + 10, dice.begin());
  13.     cout << "Let the dice be cast!\n";
  14.     // create an ostream iterator
  15.     ostream_iterator<int ,char> out_iter(cout, " ");
  16.     // copy from vector to output
  17.     copy(dice.begin(), dice.end(), out_iter);
  18.     cout << endl;
  19.     cout << "Implict use of reverse iterator.\n";
  20.     copy(dice.rbegin(), dice.rend(), out_iter);
  21.     cout << endl;
  22.     cout << endl;
  23.     cout << "Implicit use of reverse iterator.\n";
  24.     vector<int >::reverse_iterator ri;
  25.     for (ri = dice.rbegin(); ri != dice.rend(); ++ri)
  26.         cout << *ri << ' ';
  27.     cout << endl;
  28. }
  30. // insert
  31. void iteratorInsert(){
  32.     string s1[4] = {"fine", "fish", "fashion", "fate"};
  33.     string s2[2] = {"busy", "bats"};
  34.     string s3[2] = {"silly", "singers"};
  35.     vector<string> words(4);
  36.     copy(s1, s1 + 4, words.begin());
  37.     ostream_iterator<string, char> out(cout, " ");
  38.     copy(words.begin(), words.end(), out);
  39.     cout << endl;
  41.     // construct anonymous back_insert_iterator object
  42.     copy(s2, s2 + 2, back_insert_iterator<vector<string>>(words));
  43.     copy(words.begin(), words.end(), out);
  44.     cout << endl;
  46.     // construct anonymous back_insert_iterator object
  47.     copy(s3, s3 + 2, insert_iterator<vector<string>>(words, words.begin()));
  48.     copy(words.begin(), words.end(), out);
  49.     cout << endl;
  50. }
  52. int main() {
  53.     useIterator();
  54.     iteratorInsert();
  55.     return 0;
  56. }

List相关操作

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <list>
  6. using namespace std;
  8. // List的相关操作
  9. void useList(){
  10.     int stuff[5] = {1, 2, 4, 8, 6};
  11.     list<int> two;
  12.     two.insert(two.begin(), stuff, stuff + 5);
  13.     int more[6] = {6, 4, 2, 4, 6, 5};
  14.     list<int> three(two);
  15.     three.insert(three.end(), more, more + 6);
  17.     cout << "List two: ";
  18.     ostream_iterator<int , char> out(cout, " ");
  19.     copy(two.begin(), two.end(), out);
  20.     cout << endl << "List three: ";
  21.     copy(three.begin(), three.end(), out);
  22.     three.remove(2);
  23.     cout << endl << "List three minus 2s: ";
  24.     copy(three.begin(), three.end(), out);
  25.     three.splice(three.begin(), two);
  26.     cout << endl << "List three after splice: ";
  27.     three.unique();
  28.     cout << endl << "List three after unique: ";
  29.     copy(three.begin(), three.end(), out);
  30.     three.sort();
  31.     three.unique();
  32.     cout << endl << "List three after sort & unique: ";
  33.     copy(three.begin(), three.end(), out);
  34.     two.sort();
  35.     three.merge(two);
  36.     cout << endl << "Sorted two merged into three: ";
  37.     copy(three.begin(), three.end(), out);
  38.     cout << endl;
  39. }
  41. int main() {
  42.     useList();
  43.     return 0;
  44. }

程序输出

  1. List two: 1 2 4 8 6
  2. List three: 1 2 4 8 6 6 4 2 4 6 5
  3. List three minus 2s: 1 4 8 6 6 4 4 6 5
  4. List three after splice:
  5. List three after unique: 1 2 4 8 6 1 4 8 6 4 6 5
  6. List three after sort & unique: 1 2 4 5 6 8
  7. Sorted two merged into three: 1 2 4 5 6 8

Set相关操作

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <set>
  6. using namespace std;
  8. // Set的相关操作
  9. void useSet(){
  10.     const int N = 6;
  11.     string s1[N] = {"buffon", "thinkers", "for", "heavy", "can", "for"};
  12.     string s2[N] = {"metal", "any", "food", "elegant", "deliver", "for"};
  14.     set<string> A (s1, s1 + N);
  15.     set<string> B (s2, s2 + N);
  16.     ostream_iterator<string, char> out(cout, "");
  17.     cout << "Set A: ";
  18.     copy(A.begin(), A.end(), out);
  19.     cout << endl;
  20.     cout << "Set B: ";
  21.     copy(B.begin(), B.end(), out);
  22.     cout << endl;
  24.     cout << "Union of A and B: \n";
  25.     set_union(A.begin(), A.end(), B.begin(), B.end(), out);
  26.     cout << endl;
  28.     cout << "Intersection of A and B:\n";
  29.     set_intersection(A.begin(), A.end(), B.begin(), B.end(), out);
  30.     cout << endl;
  32.     cout << "Difference of A and B:\n";
  33.     set_difference(A.begin(), A.end(), B.begin(), B.end(), out);
  34.     cout << endl;
  36.     set<string> C;
  37.     cout << "Set C:\n";
  38.     set_union(A.begin(), A.end(), B.begin(), B.end(), insert_iterator<set<string>>(C, C.begin()));
  39.     copy(C.begin(), C.end(), out);
  40.     cout << endl;
  42.     string s3("grungy");
  43.     C.insert(s3);
  44.     cout << "Set C after insertion: \n";
  45.     copy(C.begin(), C.end(), out);
  46.     cout << endl;
  48.     cout << "Showing a range:\n";
  49.     copy(C.lower_bound("ghost"), C.upper_bound("spook"), out);
  50.     cout << endl;
  51. }
  53. int main() {
  54.     useSet();
  55.     return 0;
  56. }

程序输出

  1. Set A: buffoncanforheavythinkers
  2. Set B: anydeliverelegantfoodformetal
  3. Union of A and B:
  4. anybuffoncandeliverelegantfoodforheavymetalthinkers
  5. Intersection of A and B:
  6. for
  7. Difference of A and B:
  8. buffoncanheavythinkers
  9. Set C:
  10. anybuffoncandeliverelegantfoodforheavymetalthinkers
  11. Set C after insertion:
  12. anybuffoncandeliverelegantfoodforgrungyheavymetalthinkers
  13. Showing a range:
  14. grungyheavymetal

容器-multimap相关操作

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <map>
  6. using namespace std;
  8. // multimap的相关操作
  9. typedef int KeyType;
  10. typedef pair<const KeyType, string> Pairs;
  11. typedef multimap<KeyType , string> MapCode;
  12. void useMultimap(){
  13.     MapCode codes;
  15.     codes.insert(Pairs(415, "San Francisco"));
  16.     codes.insert(Pairs(510, "Oakland"));
  17.     codes.insert(Pairs(718, "Brooklyn"));
  18.     codes.insert(Pairs(718, "Staten Island"));
  19.     codes.insert(Pairs(415, "San Rafael"));
  20.     codes.insert(Pairs(510, "Berkeley"));
  22.     cout << "Number if cities with area code 415: " << codes.count(415) << endl;
  23.     cout << "Number if cities with area code 718: " << codes.count(718) << endl;
  24.     cout << "Number if cities with area code 510: " << codes.count(510) << endl;
  25.     cout << "Area Code City\n";
  26.     MapCode::iterator it;
  27.     for (it = codes.begin(); it != codes.end(); ++it){
  28.         cout << "   " << (*it).first << "   " << (*it).second << endl;
  29.     }
  30.     pair<MapCode::iterator, MapCode::iterator> range = codes.equal_range(718);
  31.     cout << "Cities with area code 718: \n";
  32.     for (it = range.first; it != range.second; ++it)
  33.         cout << (*it).second << endl;
  34. }
  36. int main() {
  37.     useMultimap();
  38.     return 0;
  39. }

程序输出

  1. Number if cities with area code 415: 2
  2. Number if cities with area code 718: 2
  3. Number if cities with area code 510: 2
  4. Area Code City
  5. 415   San Francisco
  6. 415   San Rafael
  7. 510   Oakland
  8. 510   Berkeley
  9. 718   Brooklyn
  10. 718   Staten Island
  11. Cities with area code 718:
  12. Brooklyn
  13. Staten Island

STL和String类

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <map>
  6. using namespace std;
  8. // STL和String类
  9. void stlString(){
  10.     string letters;
  11.     cout << "Enter the letter grouping (q to quit): ";
  12.     while (cin >> letters && letters != "q"){
  13.         cout << "Permutations of " << letters << endl;
  14.         sort(letters.begin(), letters.end());
  15.         cout << letters << endl;
  16.         while (next_permutation(letters.begin(), letters.end()))
  17.             cout << letters << endl;
  18.         cout << "Enter next sequence (q to quit): ";
  19.     }
  20.     cout << "Done.\n";
  21. }
  23. int main() {
  24.     stlString();
  25.     return 0;
  26. }

程序输出

  1. Enter the letter grouping (q to quit): wed
  2. Permutations of wed
  3. dew
  4. dwe
  5. edw
  6. ewd
  7. wde
  8. wed
  9. Enter next sequence (q to quit): q
  10. Done.

函数和容器方法

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <map>
  6. using namespace std;
  8. // 函数和容器方法
  9. void View(int);
  10. void View(int v){
  11.     cout << v << ' ';
  12. }
  13. const int LIMS = 10;
  14. void funList(){
  15.     int ar[LIMS] = {4, 5, 4, 2, 2, 3, 4, 8, 1, 4};
  16.     list<int> la(ar, ar + LIMS);
  17.     list<int> lb(la);
  19.     cout << "Original list contents: \n\t";
  20.     for_each(la.begin(), la.end(), View);
  21.     cout << endl;
  22.     la.remove(4);
  23.     cout << "After using the remove() method: \n";
  24.     cout << "la: \t";
  25.     for_each(la.begin(), la.end(), View);
  26.     cout << endl;
  27.     list<int>::iterator last;
  28.     last = remove(lb.begin(), lb.end(), 4);
  29.     cout << "After using the remove() function: \n";
  30.     cout << "lb: \t";
  31.     for_each(lb.begin(), lb.end(), View);
  32.     cout << endl;
  33.     lb.erase(last, lb.end());
  34.     cout << "After using the erase() method: \n";
  35.     cout << "lb: \t";
  36.     for_each(lb.begin(), lb.end(), View);
  37.     cout << endl;
  38. }
  40. int main() {
  41.     funList();
  42.     return 0;
  43. }

程序输出

  1. Original list contents:
  2. 4 5 4 2 2 3 4 8 1 4
  3. After using the remove() method:
  4. la:     5 2 2 3 8 1
  5. After using the remove() function:
  6. lb:     5 2 2 3 8 1 4 8 1 4
  7. After using the erase() method:
  8. lb:     5 2 2 3 8 1

使用STL

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <map>
  6. using namespace std;
  8. // 使用STL
  9. char toLower(char ch){ return tolower(ch); }
  10. string & ToLower(string & st);
  11. void display(const string & s);
  13. string & ToLower(string & st){
  14.     transform(st.begin(), st.end(), st.begin(), toLower);
  15.     return st;
  16. }
  18. void display(const string & s){
  19.     cout << s << " ";
  20. }
  22. void useSTL(){
  23.     vector<string> words;
  24.     cout << "Enter words (enter q to quit): \n";
  25.     string input;
  26.     while (cin >> input && input != "q")
  27.         words.push_back(input);
  28.     cout << "You entered the following words:\n";
  29.     for_each(words.begin(), words.end(), display);
  30.     cout << endl;
  31.     // place words in set, converting to lowercase
  32.     set<string> wordset;
  33.     transform(words.begin(), words.end(), insert_iterator<set<string>>(wordset, wordset.begin()), ToLower);
  34.     cout << "\nAlphabetic list of words: \n";
  35.     for_each(wordset.begin(), wordset.end(), display);
  36.     cout << endl;
  38.     // place word and frequency in map
  39.     map<string, int> wordmap;
  40.     set<string>::iterator si;
  41.     for (si = wordset.begin(); si != wordset.end(); si++)
  42.         wordmap[*si] = count(words.begin(), words.end(), *si);
  44.     // display map contents
  45.     cout << "\nWord frequency: \n";
  46.     for (si = wordset.begin(); si != wordset.end(); si++)
  47.         cout << *si << ": " << wordmap[*si] << endl;
  48. }
  50. int main() {
  51.     useSTL();
  52.     return 0;
  53. }

程序输出

  1. Enter words (enter q to quit):
  2. The dog saw the cat thought the cat fat the cat thought the cat perfact
  3. q
  4. You entered the following words:
  5. The dog saw the cat thought the cat fat the cat thought the cat perfact
  7. Alphabetic list of words:
  8. cat dog fat perfact saw the thought
  10. Word frequency:
  11. cat: 4
  12. dog: 1
  13. fat: 1
  14. perfact: 1
  15. saw: 1
  16. the: 5
  17. thought: 2

其他库的使用-Vector、valarray

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <valarray>
  6. using namespace std;
  8. // 其他STL库的使用
  9. void valvect(){
  10.     vector<double > data;
  11.     double temp;
  12.     cout << "Enter numbers(<= 0 to quit):\n";
  13.     while (cin >> temp && temp > 0)
  14.         data.push_back(temp);
  15.     sort(data.begin(), data.end());
  16.     int size = data.size();
  17.     valarray<double > numbers(size);
  18.     int i;
  19.     for (int i = 0; i < size; i++) {
  20.         numbers[i] = data[i];
  21.     }
  22.     valarray<double > sq_rts(size);
  23.     sq_rts = sqrt(numbers);
  24.     valarray<double > result(size);
  25.     result = numbers + 2.0 * sq_rts;
  26.     cout.setf(ios_base::fixed);
  27.     cout.precision(4);
  28.     for (int i = 0; i < size; i++) {
  29.         cout.width(8);
  30.         cout << numbers[i] << ": ";
  31.         cout.widen(8);
  32.         cout << result[i] << endl;
  33.     }
  34.     cout << "Done!\n";
  35. }
  37. int main() {
  38.     valvect();
  39.     return 0;
  40. }

程序输出

  1. Enter numbers(<= 0 to quit):
  2. 5 21.2 6 8 2 10 14.4 0
  3. 2.0000: 4.8284
  4. 5.0000: 9.4721
  5. 6.0000: 10.8990
  6. 8.0000: 13.6569
  7. 10.0000: 16.3246
  8. 14.4000: 21.9895
  9. 21.2000: 30.4087
  10. Done!

slice的使用

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <valarray>
  6. using namespace std;
  8. // slice的使用
  9. const int SIZE = 12;
  10. typedef valarray<int> vint;
  11. void Show_s(const vint & v, int cols);
  13. void Show_s(const vint & v, int cols){
  14.     int lim = v.size();
  15.     for (int i = 0; i < lim; i++) {
  16.         cout.width(3);
  17.         cout << v[i];
  18.         if (i % cols == cols - 1)
  19.             cout << endl;
  20.         else
  21.             cout << ' ';
  22.     }
  23.     if (lim % cols != 0)
  24.         cout << endl;
  25. }
  27. void useSlice(){
  28.     vint valint(SIZE);
  29.     for (int i = 0; i < SIZE; i++) {
  30.         valint[i] = rand() % 10;
  31.     }
  32.     cout << "Original array: \n";
  33.     Show_s(valint, 3);
  34.     vint vcol(valint[slice(1, 4, 3)]);
  35.     cout << "Second column: \n";
  36.     Show_s(vcol, 1);
  37.     valint[slice(2, 4, 3)] = 10;
  38.     cout << "Set last column to 10 :\n";
  39.     Show_s(valint, 3);
  40.     cout << "Set first column to sum of next two:\n";
  41.     valint[slice(0, 4, 3)] = vint(valint[slice(1, 4, 3)]) + vint(valint[slice(2, 4, 3)]);
  42.     Show_s(valint, 3);
  43. }
  45. int main() {
  46.     useSlice();
  47.     return 0;
  48. }

程序输出

  1. Original array:
  2. 3   3   2
  3. 9   0   8
  4. 2   6   6
  5. 9   1   1
  6. Second column:
  7. 3
  8. 0
  9. 6
  10. 1
  11. Set last column to 10 :
  12. 3   3  10
  13. 9   0  10
  14. 2   6  10
  15. 9   1  10
  16. Set first column to sum of next two:
  17. 13   3  10
  18. 10   0  10
  19. 16   6  10
  20. 11   1  10

输出输入-write

  1. #include <iostream>
  2. #include <algorithm>
  3. #include <iterator>
  4. #include <valarray>
  6. using namespace std;
  8. void useWrite(){
  9.     const char * state1 = "Florida";
  10.     const char * state2 = "Kansas";
  11.     const char * state3 = "Euphoria";
  12.     int len = strlen(state2);
  13.     cout << "Increasing loop index: \n";
  14.     for (int i = 0; i < len; i++) {
  15.         cout.write(state2, i);
  16.         cout << endl;
  17.     }
  18.     cout << "Decreasing loop index: \n";
  19.     for (int i = len; i > 0; i--)
  20.         cout.write(state2, i) << endl;
  22.     cout << "Exceeding string length:\n";
  23.     cout.write(state2, len + 5) << endl;
  24. }
  26. int main() {
  27.     useWrite();
  28.     return 0;
  29. }

程序输出

  1. Increasing loop index:
  3. K
  4. Ka
  5. Kan
  6. Kans
  7. Kansa
  8. Decreasing loop index:
  9. Kansas
  10. Kansa
  11. Kans
  12. Kan
  13. Ka
  14. K
  15. Exceeding string length:
  16. Kansas Euph