17. STL References

vector<int> v1;
vector<string> v2;
vector<FiniteAutomaton> v3;

vector<char> v4(26);

vector<float> v5(100,1.0);

<vector-size.cpp>=
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector<int> v1;
    vector<int> v2(10);
    vector<int> v3(10,7);

    cout << "v1.size() returns " << v1.size() << endl;
    cout << "v2.size() returns " << v2.size() << endl;
    cout << "v3.size() returns " << v3.size() << endl;
}

<vector-empty.cpp>=
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector<int> v1;
    vector<int> v2(10);
    vector<int> v3(10,7);

    cout << "v1.empty() has value " << v1.empty() << endl;
    cout << "v2.empty() has value " << v2.empty() << endl;
    cout << "v3.empty() has value " << v3.empty() << endl;
}

vector<int> v;
// ...
for (int i=0; i<v.size(); i++)
     cout << v[i];

vector<int> v;
// ...
for (int i=0; i<v.size(); i++)
      v[i] = 2*i;

vector<char> v(10,'a');
// ...
char ch = v.front();

vector<char> v(10,'a');
// ...
v.front() = 'b';

vector<char> v(10,'z');
// ...
char last = v.back();
v.back() = 'a';

<vector-access.cpp>=
#include <vector>
#include <iostream>

using namespace std;

int main()
{
    vector<int> v1(5);
    int x;
    cout << "Enter 5 integers (seperated by spaces):" << endl;
    for (int i=0; i<5; i++)
          cin >> v1[i];
    cout << "You entered:" << endl;
    for (int i=0; i<5; i++)
          cout << v1[i] << ' ';
    cout << endl;
}

<vector-mod.cpp>=
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector<int> v;

    for (int i=0; i<10; i++) v.push_back(i);
    cout << "Vector initialised to:" << endl;
    for (int i=0; i<10; i++) cout << v[i] << ' ' ;
    cout << endl;

    for (int i=0; i<3; i++) v.pop_back();
    cout << "Vector length now: " << v.size() << endl;
    cout << "It contains:" << endl;
    for (int i=0; i<v.size(); i++) cout << v[i] << ' ';
    cout << endl;

    int a1[5];
    for (int i=0; i<5; i++) a1[i] = 100;

    v.insert(& v[3], & a1[0],& a1[3]);
    cout << "Vector now contains:" << endl;
    for (int i=0; i<v.size(); i++) cout << v[i] << ' ';
    cout << endl;

    v.erase(& v[4],& v[7]);
    cout << "Vector now contains:" << endl;
    for (int i=0; i<v.size(); i++) cout << v[i] << ' ';
    cout << endl;
}

for (int i=0; i<v.size(); i++) { ... v[i] ... }

vector<T> v;

vector<T>::iterator i;

<vector-iterator.cpp>=
#include <iostream>
#include <vector>

using namespace std;

int main()
{
    vector<int> v(10);

    int j = 1;

    vector<int>::iterator i;

    // v를 1에서 10까지의 정수로 채운다.
    i = v.begin();
    while (i != v.end())
    {
        *i = j;
        j++;
        i++;
    }

    // v의 각 원소를 제곱한다.
    for (i=v.begin(); i!=v.end(); i++) *i = (*i) * (*i);

    // v의 내용을 출력한다.
    cout << "The vector v contains: ";
    for (i=v.begin(); i!=v.end(); i++) cout << *i << ' ';
    cout << endl;

}

(1,2,3,4) < (5,6,7,8,9,10) 는 false.
(1,2,3) < (1,2,3,4) 는 true
(1,2,3,4) < (1,2,3) 는 false
(0,1,2,3) < (1,2,3) 는 true

<vector-comp.cpp>=
#include <vector>
#include <iostream>

using namespace std;

int main()
{
    vector<int> v1;
    vector<int> v2;
    for (int i=0; i<4; i++) v1.push_back(i+1);
    for (int i=0; i<3; i++) v2.push_back(i+1);

    cout << "v1: ";
    for (int i=0; i<v1.size(); i++) cout << v1[i] << ' ';
    cout << endl;

    cout << "v2: ";
    for (int i=0; i<v2.size(); i++) cout << v2[i] << ' ';
    cout << endl;

    cout << "v1 < v2 is: " << (v1<v2 ? "true" : "false") << endl;
}

set<T, Compare> s;

set<int> s1;
set<double> s2;
set<char> s3;
set<string> s4;

<set-construct1.cpp>=
#include <iostream>
#include <set>

using namespace std;

int main()
{
    set<int> s;
    set<int>::iterator i;

    s.insert(4);
    s.insert(0);
    s.insert(-9);
    s.insert(7);
    s.insert(-2);
    s.insert(4);
    s.insert(2);

    cout << "The set contains the elements: ";
    for (i=s.begin(); i!=s.end(); i++) cout << *i << ' ';
    cout << endl;
}

<function-object.cpp>=
#include <iostream>

using namespace std;

template<class T>
class square {
public:
    T operator()(T x) { return x*x; }
};
// 이는 *가 정의되는 어떤 T에 대해서든지 쓰일 수 있다.

int main()
{
    // function object를 만든다.
    square<double> f1;
    square<int> f2;

    // 이를 사용한다.
    cout << "5.1^2 = " << f1(5.1) << endl;
    cout << "100^2 = " << f2(100) << endl;

    // 아래의 내용은 컴파일 에러를 출력할 것이다.
    // cout << "100.1^2 = " << f2(100.1) << endl;
}

template<class T>
struct less {
  bool operator()(T x, T y) { return x<y; }
}

<set-construct2.cpp>=
#include <iostream>
#include <set>

using namespace std;

// 이 class는 두 개의 멤버 변수를 갖는다.
// 오버로딩된 <은 멤버 f1값을 갖고 두 class를 비교한다.
class myClass {
private:
    int f1;
    char f2;
public:
    myClass(int a, char b) : f1(a), f2(b) {}
    int field1() const { return f1; }
    char field2() const { return f2; }
    bool operator<(myClass y) const
    { return (f1<y.field1()); }
};

// 이 function object는 멤버 f2의 값을 기초로
// myClass 타입의 객체들을 비교한다.
class comp_myClass {
public:
    bool operator()(myClass c1, myClass c2) const
    { return (c1.field2() < c2.field2()); }
};

int main()
{
    set<myClass> s1;
    set<myClass>::iterator i;
    set<myClass, comp_myClass> s2;
    set<myClass, comp_myClass>::iterator j;

    s1.insert(myClass(1,'a'));
    s2.insert(myClass(1,'a'));
    s1.insert(myClass(1,'b'));
    s2.insert(myClass(1,'b'));
    s1.insert(myClass(2,'a'));
    s2.insert(myClass(2,'a'));

    cout << "Set s1 contains: ";
    for (i=s1.begin(); i!=s1.end(); i++)
    { 
        cout << "(" << (*i).field1() << "," 
                << (*i).field2() << ")" << ' ';
    }
    cout << endl;

    cout << "Set s2 contains: ";
    for (j=s2.begin(); j!=s2.end(); j++)
    {
        cout << "(" << (*j).field1() << "," 
                << (*j).field2() << ")" << ' ';
    }
    cout << endl;
}

<printset.h>=
#ifndef _PRINTSET_H
#define _PRINTSET_H

#include <iostream>
#include <set>

template<class T, class Comp>
std::ostream& operator<<(std::ostream& os, const std::set<T,Comp>& s)
{
    std::set<T,Comp>::iterator iter = s.begin();
    int sz = s.size();
    int cnt = 0;

    os << "{";
    while (cnt < sz-1)
    {
        os << *iter << ",";
        iter++;
        cnt++;
    }
    if (sz != 0) os << *iter;
    os << "}";

    return os;
}
#endif

<set-size.cpp>=
#include <iostream>
#include <set>
#include "printset.h"

using namespace std;

int main()
{
    set<int> s;

    cout << "The set s is  "
            << (s.empty() ? "empty." : "non-empty.") << endl; 
    cout << "It has " << s.size() << "elements." << endl;

    cout << "Now adding some elements... " << endl;

    s.insert(1);
    s.insert(6);
    s.insert(7);
    s.insert(-7);
    s.insert(5);
    s.insert(2);
    s.insert(1);
    s.insert(6);

    cout << "The set s is now  
            << (s.empty() ? "empty." : "non-empty.") << endl;
    cout << "It has " << s.size() << "elements." << endl;
    cout << "s = " << s << endl;
}

<set-equality.cpp>=
#include <iostream>
#include <set>
#include "printset.h"

using namespace std;

int main()
{
    set<int> s1, s2 ,s3;

    for (int i=0; i<10; i++)
    {
        s1.insert(i);
        s2.insert(2*i);
        s3.insert(i);
    }

    cout << "s1 = " << s1 << endl;
    cout << "s2 = " << s2 << endl;
    cout << "s3 = " << s3 << endl;
    cout << "s1==s2 is: " << (s1==s2 ? true. : false.) << endl;
    cout << "s1==s3 is: " << (s1==s3 ? true. : false.) << endl;
}

<set-add-delete.cpp>=
#include <iostream>
#include <set>
#include "printset.h"

using namespace std;

int main()
{
    set<int> s1;

    // 표준적인 방식으로 원소를 추가한다.
    s1.insert(1);
    s1.insert(2);
    s1.insert(-2);

    // 특정위치에 원소 삽입
    s1.insert(s1.end(), 3);
    s1.insert(s1.begin(), -3);
    s1.insert((s1.begin()++)++, 0);

    cout << "s1 = " << s1 << endl;

    // 성공적으로 추가되었는지 체크
    pair<set<int>::iterator,bool> x = s1.insert(4);
    cout << "Insertion of 4 " << (x.second ? worked. : failed.) 
            << endl;
    x = s1.insert(0);
    cout << "Insertion of 0 " << (x.second ? worked. : failed.) 
            << endl;

    // insert에서 리턴된 iterator를 두번째 형태의 insert의 인자로
    // 사용할 수 있다.
    cout << "Inserting 10, 8 and 7." << endl;
    s1.insert(10);
    x=s1.insert(7);
    s1.insert(x.first, 8);

    cout << "s1 = " << s1 << endl;

    // 몇 원소들을 지운다.
    cout << "Removal of 0 " << (s1.erase(0) ? worked. : failed.)
            << endl;
    cout << "Removal of 5 " << (s1.erase(5) ? worked. : failed.)
            << endl;

    // 원소를 찾아서, 지운다. (find 함수는 다음 장을 참조)
    cout << "Searching for 7." << endl;
    set<int>::iterator e = s1.find(7);
    cout << "Removing 7." << endl;
    s1.erase(e);

    cout << "s1 = " << s1 << endl;

    // 마지막으로 모든 원소를 지운다.
    cout << "Removing all elements from s1." << endl;
    s1.erase(s1.begin(), s1.end());
    cout << "s1 = " << s1 << endl;
    cout << "s1 is now " << (s1.empty() ? empty. : non-empty.)
            << endl;
}

<setmember.h>=
#ifndef _SETMEMBER_H
#define _SETMEMBER_H
#include <set>

template<class T, class Comp>
bool member(T x, std::set<T,Comp>& s)
{
 return (s.count(x)==1 ? true : false);
}
#endif

// 이는 다음과 같이 쓰일 수 있다.

<set-membership.cpp>=
#include <iostream>
#include <set>
#include "printset.h"
#include "setmember.h"

using namespace std;

int main()
{
    set<int> s;
    for (int i= 0; i<10; i++) s.insert(i);
    cout << "s = " << s << endl;
    cout << "1 is " << (member(1,s) ?  : not) << " a member of s "
            <<  endl;
    cout << "10 is " << (member(10,s) ?  : not) << " a member of s "
            <<  endl;
}

      set<int> s1, s2, s3;
      // s1 과 s2의 원소를 가지고 합집합을 만든다.
      // (그러나 이런 식으로는 동작하지 않음)
      set_union(s1.begin(), s1.end(), 
                s2.begin(), s2.end(), 
                s3.begin());

      // 편의를 위해 Typedef를 사용
      typedef set<int> intSet;  
      intSet s1, s2, s3;
      // s1과 s2에 몇 원소를 추가.
      // 그리고 합집합을 구한다.
      set_union(s1.begin(), s1.end(), 
                s2.begin(), s2.end(), 
                inserter(s3,s3.begin()) );

<set-theory.cpp>=
#include <iostream>
#include <set>
#include <algorithm>
#include <iterator>
#include "printset.h"

using namespace std;

int main()
{
    typedef set<int> intSet;

    intSet s1, s2, s3, s4;

    for (int i=0; i<10; i++)
    { s1.insert(i);
        s2.insert(i+4);
    }
    for (int i=0; i<5; i++) s3.insert(i);

    cout << "s1 = " << s1 << endl;
    cout << "s2 = " << s2 << endl;
    cout << "s3 = " << s3 << endl;

    // s1이 s2의 부분집합인가?
    bool test = includes(s2.begin(),s2.end(),s1.begin(),s1.end());
    cout << "s1 subset of s2 is " << (test ? true. : false.) << endl;

    // s3가 s1의 부분집합인가?
    test = includes(s1.begin(),s1.end(),s3.begin(),s3.end());
    cout << "s3 subset of s1 is " << (test ? true. : false.) << endl;

    // s1과 s2의 합집합.
    set_union(s1.begin(), s1.end(), s2.begin(), s2.end(),
            inserter(s4,s4.begin()) );
    cout << "s1 union s2 = " << s4 << endl;

    // s4를 지우고, s1과 s2의 교집합을 구한다.
    // ( 만약 s4를 지우지 않으면 원래 s4에 들어있는 것들도
    // 같이 들어가게 될 것이다. )
    s4.erase(s4.begin(),s4.end());
    set_intersection(s1.begin(), s1.end(), s2.begin(), s2.end(),
            inserter(s4,s4.begin()) );
    cout << "s1 intersection s2 = " << s4 << endl;

    // 차집합
    s4.erase(s4.begin(),s4.end());
    set_difference(s1.begin(), s1.end(), s2.begin(), s2.end(),
            inserter(s4,s4.begin()) );
    cout << "s1 minus s2 = " << s4 << endl;

    // 차집합은 대칭적이지 않다. (즉, A-B != B-A)
    s4.erase(s4.begin(),s4.end());
    set_difference(s2.begin(), s2.end(), s1.begin(), s1.end(),
            inserter(s4,s4.begin()) );
    cout << "s2 minus s1 = " << s4 << endl;

    // 대칭차집합
    s4.erase(s4.begin(),s4.end());
    set_symmetric_difference(s1.begin(), s1.end(), s2.begin(), s2.end(),
            inserter(s4,s4.begin()) );
    cout << "s1 symmetric_difference  s2 = " << s4 << endl;

    // 대칭차집합은 대칭적이다. (즉, commutative)
    s4.erase(s4.begin(),s4.end());
    set_symmetric_difference(s2.begin(), s2.end(), s1.begin(), s1.end(),
            inserter(s4,s4.begin()) );
    cout << "s2 symmetric_difference  s1 = " << s4 << endl;
}