2015级C++第15周程序阅读 范型程序设计

阅读下面的程序，对照运行结果，领会STL的用法
(1)

#include <string>#include <set>#include <iterator>#include <iostream>using namespace std;int main(){    set <string> strset;    strset.insert("cantaloupes");    strset.insert("grapes");    strset.insert("apple");    strset.insert("orange");    strset.insert("banana");    strset.insert("grapes");    copy(strset.begin(), strset.end(), ostream_iterator<string>(cout, " "));    cout << endl;    return 0;}

(2)

#include <functional>#include <numeric>#include <vector>#include <iostream>using namespace std;int main(){    vector<int> v(5);    for (int i = 0; i < 5; i++)        v[i] = i + 1;    int sum = accumulate(v.begin(), v.end(), 0);    cout << "Sum of values == " << sum << endl;    int product = accumulate(v.begin(), v.end(), 1, multiplies<long>());    cout << "Product of values == " << product << endl;    return 0;}

(3)

#include <algorithm>#include <functional>#include <vector>#include <iostream>#include <numeric>#include <iterator>using namespace std;int main(){    int a[] = {1,4,7,2,5,8};    int b[] = {1,2,3,3,2,1};    const int ASZ = sizeof a / sizeof a[0];    const int BSZ = sizeof b / sizeof b[0];    ostream_iterator<int> out(cout,"  ");    copy(a, a + ASZ, out);    cout<<endl;    copy(b, b + BSZ, out);    cout<<endl;    int r = accumulate(a, a + ASZ, 0);    cout << "accumulate 1: " << r << endl;    // Should produce the same result:    r = accumulate(b, b + BSZ, 0, plus<int>());    cout << "accumulate 2: " << r << endl;    r = inner_product(a, a + ASZ, b, 0);    // 或  r = inner_product(a, a + ASZ, b, 0, plus<int>(), multiplies<int>());    cout << "inner_product : " << r << endl;    int* it = partial_sum(a, a + ASZ, b);    // 或 int* it = partial_sum(a, a + ASZ, b, plus<int>());    copy(b, it, out);    cout<<endl;    it = adjacent_difference(a, a + ASZ, b);    // 或 it = adjacent_difference(a, a + ASZ, b, minus<int>());    copy(b, it, out);    cout<<endl;    return 0;}

(4)

#include <algorithm>#include <functional>#include <iostream>#include <vector>#include <iterator>using namespace std;class myAdd: public binary_function<int,int,int>{public:    int operator()(int a, int b) const    {        return a+b;    }};int main(){    int a[5]= {1,2,3,4,5};    vector<int> my(5);    transform(a,a+5,my.begin(), bind2nd(myAdd(), 4));    copy(my.begin(), my.end(), ostream_iterator<int>(cout, " "));    cout<<endl;    transform(a,a+5,a,my.begin(), myAdd());    copy(my.begin(), my.end(), ostream_iterator<int>(cout, " "));    cout<<endl;    return 0;}

(5)

#include <iterator>#include <algorithm>#include <functional>#include <iostream>#include <vector>using namespace std;class Angle{    int degrees;public:    Angle(int deg) : degrees(deg) {}    int mul(int times)    {        return degrees *= times;    }};int main(){    int x[] = {1, 2, 4, 5, 8};    vector<Angle> va;    for(int i =10; i <= 50; i += 10)        va.push_back(Angle(i));    transform(va.begin(), va.end(), x, ostream_iterator<int>(cout , "  "), mem_fun_ref(&Angle::mul));    cout << endl;    return 0;}

(6)

#include <string>#include <iostream>#include <map>using namespace std;class CStudent{public :    int nStudentID;    int nAge;public :    CStudent()  {  }    CStudent(int nSID, int nA)    {        nStudentID=nSID;        nAge=nA;    }    //复制构造函数    CStudent(const CStudent& ob)     {        nStudentID=ob.nStudentID;        nAge=ob.nAge;    }};int main(){    map <string, CStudent> mapStudent;    mapStudent["zhangsan"] = CStudent(100012, 22);    mapStudent["Lisi"] = CStudent(100085, 21);    mapStudent["Wangwu"] = CStudent(100093, 23);    cout << "The Student number for Lisi  is " <<(mapStudent["Lisi"].nStudentID) << endl;    return 0;}