C++ Sans CS106B Demystifying genlib.h Simplified genlib.h Contents - - PowerPoint PPT Presentation

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C++ Sans CS106B Demystifying genlib.h Simplified genlib.h Contents - - PowerPoint PPT Presentation

Nov 08, 2023 251 likes •770 views

C++ Sans CS106B Demystifying genlib.h Simplified genlib.h Contents #ifndef _genlib_h #define _genlib_h #include <string> using namespace std; void Error(string str); #endif Simplified genlib.h Contents #ifndef _genlib_h #define _genlib_h

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C++ Sans CS106B

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Demystifying genlib.h

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Simplified genlib.h Contents

#ifndef _genlib_h #define _genlib_h #include <string> using namespace std; void Error(string str); #endif

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Simplified genlib.h Contents

#ifndef _genlib_h #define _genlib_h #include <string> using namespace std; void Error(string str); #endif

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Simplified genlib.h Contents

#ifndef _genlib_h #define _genlib_h #include <string> using namespace std; void Error(string str); #endif

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Simplified genlib.h Contents

#ifndef _genlib_h #define _genlib_h #include <string> using namespace std; void Error(string str); #endif

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#include <iostream> int main() { cout << "C++ FTW!" << endl; return 0; }

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The Standard Namespace (namespace std)

#include <iostream> int main() { cout << "C++ FTW!" << endl; return 0; }

cout cin string endl

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The Standard Namespace (namespace std)

cout cin string endl

#include <iostream> int main() { cout << "C++ FTW!" << endl; return 0; } Impenetrable barrier!

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The Standard Namespace (namespace std) The Standard Namespace (namespace std)

cout cin string endl

#include <iostream> using namespace std; int main() { cout << "C++ FTW!" << endl; return 0; } Impenetrable barrier!

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Summary of genlib.h

  • Includes the standard string type through

#include <string>

  • Prototypes Error.
  • Imports standard names with

using namespace std;

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The Standard Template Library (STL)

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STL Hierarchy

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STL Hierarchy

CONTAINERS

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ITERATORS

STL Hierarchy

CONTAINERS

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ITERATORS ALGORITHMS

STL Hierarchy

CONTAINERS

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ITERATORS ALGORITHMS FUNCTORS

STL Hierarchy

CONTAINERS

ALLOCATORS ADAPTERS

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STL Containers

  • Standard C++ version of the CS106 ADTs.
  • Nothing fundamentally new – skills from CS106

transferable with some name changes.

  • No Grid, sorry...
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CS106 Vector to STL vector

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CS106 Vector to STL vector

#include "vector.h" #include <iostream> using namespace std; const int NUM_INTS = 10; int main() { Vector<int> v; for(int i = 0; i < NUM_INTS; i++) v.add(i); for(int i = 0; i < v.size(); i++) cout << v[i] << endl; }

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CS106 Vector to STL vector

#include <vector> #include <iostream> using namespace std; const int NUM_INTS = 10; int main() { Vector<int> v; for(int i = 0; i < NUM_INTS; i++) v.add(i); for(int i = 0; i < v.size(); i++) cout << v[i] << endl; }

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CS106 Vector to STL vector

#include <vector> #include <iostream> using namespace std; const int NUM_INTS = 10; int main() { vector<int> v; for(int i = 0; i < NUM_INTS; i++) v.add(i); for(int i = 0; i < v.size(); i++) cout << v[i] << endl; }

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CS106 Vector to STL vector

#include <vector> #include <iostream> using namespace std; const int NUM_INTS = 10; int main() { vector<int> v; for(int i = 0; i < NUM_INTS; i++) v.push_back(i); for(int i = 0; i < v.size(); i++) cout << v[i] << endl; }

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foreach is a CS106B-specific invention.

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That means that there is no foreach in the STL.

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Instead, the STL uses iterators.

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STL Iterators

  • Generalization of a pointer.
  • Used to iterate over containers.
  • More verbose than foreach, but more

powerful.

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Basic Iterator Patterns

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) *itr = 137;

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Basic Iterator Patterns

Vector<int> myVector; foreach(int x in myVector) cout << x << endl; vector<int> stlVec; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) cout << *itr << endl; for(vector<int>::iterator itr = stlVec.begin(); itr != stlVec.end(); ++itr) *itr = 137; set<int> stlSet; for(set<int>::iterator it = stlSet.lower_bound(3); it != stlVec.upper_bound(137); ++it) cout << *it << endl;

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STL Algorithms

  • No parallel in the CS106 libraries.
  • 75 generic algorithms to apply to ranges of

data.

  • Usually operate on iterator ranges.
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STL Algorithms Example

vector<int> v; const int NUM_INTS = 200; v.resize(NUM_INTS); generate(v.begin(), v.end(), rand); sort(v.begin(), v.end()); if(binary_search(v.begin(), v.end(), 137)) cout << "Found 137!" << endl; else cout << "Awww..." << endl;

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STL Algorithms Example

vector<int> v; const int NUM_INTS = 200; v.resize(NUM_INTS); generate(v.begin(), v.end(), rand); sort(v.begin(), v.end()); if(binary_search(v.begin(), v.end(), 137)) cout << "Found 137!" << endl; else cout << "Awww..." << endl;

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More STL Algorithms

bool IsPalindrome(string str)

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More STL Algorithms

bool IsPalindrome(string str) { return equal(str.begin(), str.end(), str.rbegin()); }

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Even More STL Algorithms

string ConvertToUpperCase(string str)

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Even More STL Algorithms

string ConvertToUpperCase(string str) { transform(str.begin(), str.end(), str.begin(), ::toupper); return str; }

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More STL Algorithms Than That

vector<vector<int> > AllPermutations(vector<int> input)

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More STL Algorithms Than That

vector<vector<int> > AllPermutations(vector<int> input) { vector<vector<int> > result; sort(input); do result.push_back(input); while(next_permutation(input.begin(), input.end())); return result; }

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Summary of the STL

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Containers store data.

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Iterators define ranges.

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Algorithms let you sleep earlier.