{"id":2171,"date":"2025-01-28T19:41:24","date_gmt":"2025-01-28T19:41:24","guid":{"rendered":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/?page_id=2171"},"modified":"2025-01-28T21:36:07","modified_gmt":"2025-01-28T21:36:07","slug":"generic-algorithms","status":"publish","type":"page","link":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/topics\/c-details\/the-standard-template-library-2\/generic-algorithms\/","title":{"rendered":"Generic Algorithms"},"content":{"rendered":"\n

<\/span>Generic Algorithms<\/span><\/h2>\n\n\n\n

We’ve already seen one generic algorithm: reverse()<\/strong>.<\/p>\n\n\n\n

<\/span>find()<\/span><\/h3>\n\n\n\n

Another generic algorithm is find()<\/strong>.<\/p>\n\n\n\n

Here’s an example using a regular array of chars:<\/p>\n\n\n\n

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<\/path><\/path><\/svg><\/span>
\/\/<\/span><\/span>\n\/\/  FindExample.cpp<\/span><\/span>\n\/\/  STL Sequence Containers<\/span><\/span>\n\/\/<\/span><\/span>\n\/\/  Created by Bryan Higgs on 10\/20\/24.<\/span><\/span>\n\/\/<\/span><\/span>\n<\/span>\n#include<\/span> <\/span><iostream><\/span><\/span>\n#include<\/span> <\/span><algorithm><\/span>  <\/span>\/\/ For find()<\/span><\/span>\n<\/span>\nint<\/span> <\/span>main<\/span>(<\/span>int<\/span> <\/span>argc<\/span>, <\/span>const<\/span> <\/span>char<\/span> <\/span>*<\/span> <\/span>argv<\/span>[])<\/span><\/span>\n{<\/span><\/span>\n  <\/span>char<\/span> s[] = <\/span>"Example of generic find algorithm"<\/span>;<\/span><\/span>\n  <\/span>size_t<\/span> len = <\/span>strlen<\/span>(s);<\/span><\/span>\n  <\/span>const<\/span> <\/span>char<\/span> *foundChar = <\/span>std<\/span>::<\/span>find<\/span>(&<\/span>s<\/span>[<\/span>0<\/span>], &<\/span>s<\/span>[len], <\/span>'g'<\/span>);<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>"Found character: "<\/span> << *foundChar << <\/span>std<\/span>::endl<\/span><\/span>\n            << <\/span>"Next character: "<\/span> << *(foundChar+<\/span>1<\/span>) << <\/span>std<\/span>::endl;<\/span><\/span>\n  <\/span><\/span>\n  <\/span>return<\/span> <\/span>0<\/span>;<\/span><\/span>\n}<\/span><\/span><\/code><\/pre><\/div>\n<\/div>\n\n\n\n
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… which outputs:<\/p>\n\n\n\n
Found character: g\nNext character: e\nProgram ended with exit code: 0<\/strong><\/code><\/pre>\n<\/div>\n<\/div>\n\n\n\n
Here’s how you can use find()<\/strong> with a std::vector<\/strong> :<\/p>\n\n\n\n
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<\/path><\/path><\/svg><\/span>
\/\/<\/span><\/span>\n\/\/  FindExample2.cpp<\/span><\/span>\n\/\/  STL Sequence Containers<\/span><\/span>\n\/\/<\/span><\/span>\n\/\/  Created by Bryan Higgs on 10\/20\/24.<\/span><\/span>\n\/\/<\/span><\/span>\n<\/span>\n#include<\/span> <\/span><iostream><\/span><\/span>\n#include<\/span> <\/span><vector><\/span>  <\/span>\/\/ For vector<\/span><\/span>\n#include<\/span> <\/span><algorithm><\/span>  <\/span>\/\/ For find()<\/span><\/span>\n<\/span>\n#include<\/span> <\/span>"Make.h"<\/span><\/span>\n<\/span>\nint<\/span> <\/span>main<\/span>(<\/span>int<\/span> <\/span>argc<\/span>, <\/span>const<\/span> <\/span>char<\/span> <\/span>*<\/span> <\/span>argv<\/span>[])<\/span><\/span>\n{<\/span><\/span>\n  <\/span>std<\/span>::vector<<\/span>char<\/span>> v = <\/span>make<\/span>< <\/span>std<\/span>::<\/span>vector<\/span><<\/span>char<\/span>> >(<\/span><\/span>\n        <\/span>"Example of generic find algorithm"<\/span>);<\/span><\/span>\n  <\/span>std<\/span>::<\/span>vector<\/span><<\/span>char<\/span>>::iterator foundChar<\/span><\/span>\n        = <\/span>find<\/span>(<\/span>v<\/span>.<\/span>begin<\/span>(), <\/span>v<\/span>.<\/span>end<\/span>(), <\/span>'g'<\/span>);<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>"Found character: "<\/span> << *foundChar << <\/span>std<\/span>::endl<\/span><\/span>\n            << <\/span>"Next character: "<\/span> << *(foundChar+<\/span>1<\/span>) << <\/span>std<\/span>::endl;<\/span><\/span>\n<\/span>\n  <\/span>return<\/span> <\/span>0<\/span>;<\/span><\/span>\n}<\/span><\/span><\/code><\/pre><\/div>\n<\/div>\n\n\n\n
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… which outputs the exact same thing as the previous example:<\/p>\n\n\n\n
Found character: g\nNext character: e\nProgram ended with exit code: 0<\/strong><\/code><\/pre>\n<\/div>\n<\/div>\n\n\n\n
<\/span>merge()<\/span><\/h3>\n\n\n\n
Another generic algorithm from the STL is merge()<\/strong>, which combines the contents of two sorted sequences into a single sorted sequence:<\/p>\n\n\n\n
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<\/path><\/path><\/svg><\/span>
\/\/<\/span><\/span>\n\/\/  MergeExample.cpp<\/span><\/span>\n\/\/  STL Sequence Containers<\/span><\/span>\n\/\/<\/span><\/span>\n\/\/  Created by Bryan Higgs on 10\/20\/24.<\/span><\/span>\n\/\/<\/span><\/span>\n<\/span>\n#include<\/span> <\/span><iostream><\/span><\/span>\n#include<\/span> <\/span><list><\/span>     <\/span>\/\/ For list<\/span><\/span>\n#include<\/span> <\/span><deque><\/span>    <\/span>\/\/ For deque<\/span><\/span>\n#include<\/span> <\/span><algorithm><\/span>\/\/ For merge<\/span><\/span>\n<\/span>\n#include<\/span> <\/span>"make.h"<\/span><\/span>\n<\/span>\nint<\/span> <\/span>main<\/span>(<\/span>int<\/span> <\/span>argc<\/span>, <\/span>const<\/span> <\/span>char<\/span> <\/span>*<\/span> <\/span>argv<\/span>[])<\/span><\/span>\n{<\/span><\/span>\n  <\/span>char<\/span> vowels[] = <\/span>"aeiou"<\/span>;<\/span><\/span>\n  <\/span>size_t<\/span> len = <\/span>strlen<\/span>(vowels);<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>"Vowels: "<\/span> << vowels << <\/span>std<\/span>::endl;<\/span><\/span>\n  <\/span><\/span>\n  <\/span>std<\/span>::list<<\/span>char<\/span>> consonants<\/span><\/span>\n    = <\/span>make<\/span>< <\/span>std<\/span>::<\/span>list<\/span><<\/span>char<\/span>> >(<\/span>"bcdfghjklmnpqrstvwxyz"<\/span>);<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>"Consonants: "<\/span>;<\/span><\/span>\n  <\/span>for<\/span> (<\/span>char<\/span> c: consonants)<\/span><\/span>\n  {<\/span><\/span>\n    <\/span>std<\/span>::cout << c;<\/span><\/span>\n  }<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>std<\/span>::endl;<\/span><\/span>\n  <\/span><\/span>\n  <\/span>std<\/span>::deque<<\/span>char<\/span>> <\/span>letters<\/span>(<\/span>26<\/span>, <\/span>'X'<\/span>);<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>"Letters (initial) : "<\/span>;<\/span><\/span>\n  <\/span>for<\/span> (<\/span>char<\/span> c: letters)<\/span><\/span>\n  {<\/span><\/span>\n    <\/span>std<\/span>::cout << c;<\/span><\/span>\n  }<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>std<\/span>::endl;<\/span><\/span>\n  <\/span><\/span>\n  <\/span>merge<\/span>(&<\/span>vowels<\/span>[<\/span>0<\/span>], &<\/span>vowels<\/span>[len],<\/span><\/span>\n        <\/span>consonants<\/span>.<\/span>begin<\/span>(), <\/span>consonants<\/span>.<\/span>end<\/span>(),<\/span><\/span>\n        <\/span>letters<\/span>.<\/span>begin<\/span>()<\/span><\/span>\n        );<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>"Letters (final) : "<\/span>;<\/span><\/span>\n  <\/span>for<\/span> (<\/span>char<\/span> c: letters)<\/span><\/span>\n  {<\/span><\/span>\n    <\/span>std<\/span>::cout << c;<\/span><\/span>\n  }<\/span><\/span>\n  <\/span>std<\/span>::cout << <\/span>std<\/span>::endl;<\/span><\/span>\n  <\/span><\/span>\n  <\/span>return<\/span> <\/span>0<\/span>;<\/span><\/span>\n}<\/span><\/span><\/code><\/pre><\/div>\n<\/div>\n\n\n\n
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… which outputs the exact same thing as the previous example:<\/p>\n\n\n\n
Vowels: aeiou\nConsonants: bcdfghjklmnpqrstvwxyz\nLetters (initial) : XXXXXXXXXXXXXXXXXXXXXXXXXX\nLetters (final) : abcdefghijklmnopqrstuvwxyz\nProgram ended with exit code: 0<\/strong><\/code><\/pre>\n<\/div>\n<\/div>\n\n\n\n
<\/div>\n\n\n\n
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Next: Iterators<\/a><\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"
Generic Algorithms We’ve already seen one generic algorithm: reverse(). find() Another generic algorithm is find(). Here’s an example using a regular array of chars: … which outputs: Here’s how you can use find() with a std::vector : … which outputs the exact same thing as the previous example: merge() Another generic algorithm from the STL […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2150,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-2171","page","type-page","status-publish","hentry"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/pages\/2171","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/comments?post=2171"}],"version-history":[{"count":3,"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/pages\/2171\/revisions"}],"predecessor-version":[{"id":2221,"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/pages\/2171\/revisions\/2221"}],"up":[{"embeddable":true,"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/pages\/2150"}],"wp:attachment":[{"href":"https:\/\/bhiggs.x10hosting.com\/PracticalCPlusPlusProgramming\/index.php\/wp-json\/wp\/v2\/media?parent=2171"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}