STL_算法_填充新值(fill、fill_n、generate、generate_n)
阿新 • • 發佈:2017-07-02
mil str mar data ace pla lis margin rate
C++ Primer 學習中。。。
簡單記錄下我的學習過程 (代碼為主)
全部容器適用
fill(b,e,v) //[b,e) 填充成v
fill_n(b,n,v) //[b,b+n) 填充成v
generate(b,e,p) //[b,e) 依照p方法填充
generate_n(b,n,p) //[b,b+n) 依照p方法填充
/**------http://blog.csdn.net/u010579068------**/ #include<iostream> #include<cstdio> #include<string> #include<vector> #include<list> #include<deque> #include<ctime> #include<algorithm> using namespace std; /***************************************** //全部容器適用 fill(b,e,v) //[b,e) 填充成v fill_n(b,n,v) //[b,b+n) 填充成v generate(b,e,p) //[b,e) 依照p方法填充 generate_n(b,n,p) //[b,b+n) 依照p方法填充 *****************************************/ /**---------------------------------------------------------------------------------- ----------------------------------------------------------------------------------**/ /************************************************************************************* std::fill 全部排序容器適用 algorithm -------------------------------------------------------------------------------------- template < class ForwardIterator, class T > void fill ( ForwardIterator first, ForwardIterator last, const T& value ); //eg: template < class ForwardIterator, class T > void fill ( ForwardIterator first, ForwardIterator last, const T& value ) { while (first != last) *first++ = value; } *************************************************************************************/ /************************************************************************************* std::fill_n 全部排序容器適用 algorithm -------------------------------------------------------------------------------------- template < class OutputIterator, class Size, class T > void fill_n ( OutputIterator first, Size n, const T& value ); //eg: template < class OutputIterator, class Size, class T > void fill_n ( OutputIterator first, Size n, const T& value ) { for (; n>0; --n) *first++ = value; } *************************************************************************************/ /************************************************************************************* std::generate 全部排序容器適用 algorithm -------------------------------------------------------------------------------------- template <class ForwardIterator, class Generator> void generate ( ForwardIterator first, ForwardIterator last, Generator gen ); //eg: template <class ForwardIterator, class Generator> void generate ( ForwardIterator first, ForwardIterator last, Generator gen ) { while (first != last) *first++ = gen(); } *************************************************************************************/ /************************************************************************************* std::generate_n 全部排序容器適用 algorithm -------------------------------------------------------------------------------------- template <class OutputIterator, class Size, class Generator> void generate_n ( OutputIterator first, Size n, Generator gen ); //eg: template <class OutputIterator, class Size, class Generator> void generate_n ( OutputIterator first, Size n, Generator gen ) { for (; n>0; --n) *first++ = gen(); } *************************************************************************************/ // function generator: int RandomNumber () { return (rand()%100); } // class generator: struct c_unique { int current; c_unique() { current=0; } int operator()() { return ++current; } } UniqueNumber; int current(0); int Unique_Number () { return ++current; } int main() { vector<int> myvector (8); // myvector: 0 0 0 0 0 0 0 0 fill (myvector.begin(),myvector.begin()+4,5); // myvector: 5 5 5 5 0 0 0 0 fill (myvector.begin()+3,myvector.end()-2,8); // myvector: 5 5 5 8 8 8 0 0 cout << "myvector contains:"; for (vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it) cout << " " << *it; cout << endl; /**---------------------------------------------------------------------------------**/ deque<int> mydeque (8,10); // mydeque: 10 10 10 10 10 10 10 10 fill_n (mydeque.begin(),4,20); // mydeque: 20 20 20 20 10 10 10 10 fill_n (mydeque.begin()+3,3,33); // mydeque: 20 20 20 33 33 33 10 10 cout << "mydeque contains:"; for (deque<int>::iterator it=mydeque.begin(); it!=mydeque.end(); ++it) cout << " " << *it; cout << endl; /**---------------------------------------------------------------------------------**/ srand ( unsigned ( time(NULL) ) ); // vector<int> myvector (8); vector<int>::iterator it; generate (myvector.begin(), myvector.end(), RandomNumber); cout << "myvector contains:"; for (it=myvector.begin(); it!=myvector.end(); ++it) cout << " " << *it; generate (myvector.begin(), myvector.end(), UniqueNumber); cout << "\nmyvector contains:"; for (it=myvector.begin(); it!=myvector.end(); ++it) cout << " " << *it; cout << endl; /**---------------------------------------------------------------------------------**/ int myarray[9]; generate_n (myarray, 9, Unique_Number); cout << "myarray contains:"; for (int i=0; i<9; ++i) cout << " " << myarray[i]; cout << endl; return 0; } /****** Output: myvector contains: 5 5 5 8 8 8 0 0 mydeque contains: 20 20 20 33 33 33 10 10 myvector contains: 64 12 31 25 35 67 20 6 myvector contains: 1 2 3 4 5 6 7 8 myarray contains: 1 2 3 4 5 6 7 8 9 ******/
STL_算法_填充新值(fill、fill_n、generate、generate_n)